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Amethyst Galleries' Mineral Gallery Category: Hobbies and Crafts > Amethysts Date & country: 23/09/2019, US Words: 192

Adamite
(Zinc Arsenate Hydroxide) Adamite is a favorite among collectors of fluorescent minerals because of its consistent bright green fluorescence under short and long UV light. It also makes a wonderful mineral specimen in ordinary light. The typical lime green color of its adamantine (high luster) crystals set on top of its commonly...

Aegirine
(Sodium Iron Silicate) Aegirine , which is listed in some guides as acmite, forms impressive crystals that have become classics among collectors. These tall opaque monument-like crystals that jut majestically out from their host rocks are simply splendid. The steeply inclined pyramid on top of the prismatic crystals is very cha...

Ajoite
(Hydrated Potassium Sodium Copper Aluminum Silicate Hydroxide) Ajoite is an attractive copper silicate mineral that is named for its type locality in the Ajo District of Pima County, Arizona . It is a secondary mineral that forms from the oxidation of other secondary copper minerals. Ajoite forms excellent microcrystal spec...

Alluvial Deposits
Alluvial Deposits are unconsolidated sediments that have been deposited by running water. This results in sorting of materials, as large blocks are dropped quickly while smaller materials travel farther before settling out of the water. Generally, fast flowing water picks up materials and slow flowing water drops them. When a stream or r...

Allanite
(Calcium Rare Earth Aluminum Iron Silicate Hydroxide) Allanite, also known as `orthite` in Europe, is one of the most common rare earth minerals, which is somewhat of an oxymoron. Rare earth elements include many unusual and valuable metals. Up to 20% of allanite's weight could be composed of these rare earth elemen...

Albite
(Sodium Aluminum Silicate) Albite is a common felspar and is the `pivot` mineral of two different feldspar series. It is most often associated with the plagioclase series where it is an end member of this series. The plagioclase series comprises felspars that range in chemical composition from pure NaAlSi 3 O 8 to pure CaAl 2 ...

Alunite
(Potassium Aluminum Sulfate Hydroxide) Alunite is also known as alumstone and is a source of the chemical known as alum, KAl(SO 4 ) 2 - 12H 2 O. Some alunite has also been used to recover potassium and aluminum. Alunite forms from the action of sulfuric acids upon potassium rich feldspars in a process cal...

Altaite
(Lead Telluride) Altaite is a member of the Galena Group of minerals. Its properties are very similar to galena as it shares basically the same structure. However it is easily distinguished from the far more common galena by its white to yellowish white color and greater density. Not too many minerals are greater in density t...

Andesine
(Sodium Calcium Aluminum Silicate) Andesine is only a minor constituent in most granites and syenites. But is the dominant feldspar in certain igneous rocks called, appropriately andesites. It is also found in some metamorphic rocks as a minor constituent. Andesine is a member of the Plagioclase Feldspar Group. The plagioclas...

Anatase
(Titanium Oxide) Anatase is a polymorph with two other minerals. The minerals rutile and brookite as well as anatase all have the same chemistry, TiO 2 , but they have different structures. At higher temperatures, about 915 degrees Celsius, anatase will automatically revert to the rutile structure. Rutile is the more commo...

Anapaite
(Hydrated Calcium Iron Phosphate) Anapaite is rare and beautiful phosphate mineral. Or is it? Some mineral purists would dispute anapaite's inclusion into the mineral kingdom. The reason is that anapaite has a somewhat organic origin. In true pure mineralogical tradition, a mineral must have inorganic origins (ie. it is not made...

Analcime
(Hydrated Sodium Aluminum Silicate) Analcime is a popular and interesting mineral. It is sometimes known as analcite, although analcime is preferred. It is one of the few minerals that characteristically forms its own unique crystal. Well, not quite its own unique crystal, but pretty close. It forms the isometric trapezohedron ....

Antimony
Antimony does not often form in its elemental state and is far more common in sulfides and sulfosalts such as stibnite , tetrahedrite , bournonite , boulangerite and jamesonite . It is also found in some oxides such as valentinite , stibiconite and senarmontite Due to the abundance of these antimony bearing ores and the rarity of n...

Anorthosite
Anorthosite is a plutonic igneous rock, primarily consisting of plagioclase feldspars with no more than 10% of mafic components such as ilmenite , olivene , magnetite or pyroxene .

Andesite
Andesite is an extrusive igneous rock consisting primarily of plagioclase feldspars plus pyroxene and/or hornblende . Biotite , magnetite , quartz and sphene are common constituents.

Ankerite
(Calcium Iron Magnesium Manganese Carbonate) Ankerite is named after Professor M. J. Anker, an Austrian mineralogist. Ankerite's formula is often written as CaFe(CO₃)₂ ; but there is actually a significant amount of magnesium amd manganese substitution for the iron and so the formu...

Apatite
(Calcium (Fluoro-, Chloro-, Hydroxyl-) Apatite is actually three different minerals depending on the predominance of either fluorine, chlorine or the hydroxyl group. These ions can freely substitute in the crystal lattice and all three are usually present in every specimen although some specimens have been close to 100% in one o...

Arsenic
Arsenic is historically the poison of choice for many murders, in reality and in fiction. Here, arsenic is dealt with only as mineral specimens and is not to be ingested. Although it has been used as a poison, arsenic has many chemical uses and is quite an important element. Arsenic does not often form in its elemental state and is far more common...

Artinite
(Hydrated Magnesium Carbonate Hydroxide) Artinite is a somewhat rare carbonate mineral. It forms as a crust of acicular to fibrous crystal aggregates sometimes collected into tight perfectly spherical balls. It is always associated with ultra-basic igneous and metamorphic rocks such as serpentinite. It often surprises people w...

Asteroids
Asteroids include the rocky bodies that occupy the main asteroid belt, a field occupying the region between Mars and Jupiter, and other small rocky bodies orbiting the Sun. The main asteroid belt may be the location of a planet that failed to form; certainly the largest asteroid, Ceres, orbits precisely where predicted by Bode's Law (au = 0.4 + 0...

Augite
(Calcium Sodium Magnesium Iron Aluminum Silicate) Augite is an important rock-forming mineral in many igneous rocks, especially in gabbros and basalts, and is also found in some hydrothermal metamorphic rocks. Augite is a part of an important solid solution series of the pyroxene group. The series includes the minerals hedenbe...

Augelite
(Aluminum Phosphate Hydroxide) Augelite is not a well known phosphate mineral. It is difficult to recognize, especially when found as clear and colorless tiny crystals. Augelite is found in granitic pegmatites, but mostly in hydrothermal veins. The best locality for good crystals is White Mountain, Mono County, California. Up...

Autunite
(Hydrated Calcium Uranyl Phosphate) Autunite is one of the more attractive and popular radioactive minerals. To state the obvious, the uranium in its chemical formula provides this radioactivity. Autunite is probably the most popular uranium mineral for collectors. Its green and yellow color shades seem to glow and are actually ...

Axinite
(Calcium Manganese Iron Magnesium Aluminum Borosilicate Hydroxide) Axinite is an interesting mineral and produces unique flattened spatula shaped crystals that fanciers of well formed crystals love to collect. It is a triclinic mineral which means that it has no symmetry planes or axes of rotation. It does possess a center of...

Barite
(Barium Sulfate) Barite is a common mineral and makes very attractive specimens. It often is an accessory mineral to other minerals and can make a nice backdrop to brightly colored crystals. At times bladed or tabular crystals of Barite form a concentric pattern of increasingly larger crystals outward. This has the appearance...

Basalt
Basalt is a very common igneous rock. In fact it is the most common rock in the Earth's crust. Almost all oceanic crust is made of basalt and basalt is a common extrusion from many volcanic regions around the world. It forms from the melting of the upper mantle and its chemistry closely resembles the upper mantle's composition. It is generally...

Banded Iron Formation
Banded Iron Formation (also known as BIF , or as taconite in North America) is a term that is applied to a very unique sedimentary rock of biochemical origin. These rocks are unique in their make up, unique in their age and unique in their origins. They are found all over the world, but only in certain areas of all the major continents. Ever...

Bakerite
(Hydrated Calcium Boro-silicate Hydroxide) Bakerite is a rare boro-silicate that was discovered in Death Valley, California and is still only found in abundance there. It is found there in altered volcanic rocks as nodules and veins. Datolite and howlite a couple of other boro-silicates, form similar looking nodules, but d...

Betafite
(Calcium Sodium Uranium Titanium Niobium Tantalum Oxide Hydroxide Fluoride) Betafite is a popular uranium bearing mineral to collect. It is one of the few uranium minerals to form nice well shaped crystals. Betafite crystallizes in the isometric symmetry class and forms large octahedral and dodecahedral crystals that can weig...

Beryl
(Beryllium Aluminum Silicate) Beryl is often unknown to the general public, even the gemstone-buying public. However, it is one of the most important gem minerals. Beryl is colorless in pure form; it is the many different impurities that give beryl its varied coloration. Without these splendid color varieties, beryl would be ...

Bixbyite
(Manganese Iron Oxide) Bixbyite is a rare mineral, but is still well known among collectors. It forms well formed isometric crystals, usually highly modified cubes. It also is associated with several interesting and attractive minerals and has a nice high luster. For these reasons bixbyite is popular among collectors although it...

Bismuth
Bismuth is rarely found in nature in its elemental form. Of growing interest in rock shops, however, are laboratory-grown bismuth crystals. These crystals, while not natural, are nonetheless very interesting to the mineral hobbyist and to others. The unique look that these clusters offer is really indescribable. Its color consisits of iridescent me...

Biotite
(Potassium Iron Magnesium Aluminum Silicate Hydroxide Fluoride) Biotite is a common rock forming mineral, being present in at least some percentage in most igneous and both regional and contact metamorphic rocks. The typical black to brown color of biotite is characteristic although it is difficult to distinguish brown biotite ...

Blodite
(Hydrated Sodium Magnesium Sulfate) Blodite, which is also spelled bloedite, forms in marine and non-marine (lacustrine) evaporite deposits. Evaporite minerals are geologically important because they clearly are related to the environmental conditions that existed at the time of their deposition, namely arid. ...

Boleite
(Hydrated Lead Copper Silver Chloride Hydroxide) Boleite is a mineral of crystallographic curiosity and of great interest to collectors of twins , silver minerals and rare halides. And hey . . . its pretty too! Its indigo blue color is distinctive and attractive and some crystals are cut as gemstones. Boleite is technically a...

Boracite
(Magnesium Borate Chloride) Boracite is an interesting borate mineral. It has good color, clarity and hardness to be a gemstone and yet it is rarely cut for this purpose. Probably because it is slightly soluble in water and ordinary wear dulls its surface. It is an attractive mineral for mineral specimens though. Boracite is s...

Borax
(Hydrated Sodium Borate) Borax is a complex borate mineral that is found in playa lakes and other evaporite deposits. The basic structure of borax contains chains of interlocking BO 2 (OH) triangles and BO 3 (OH) tetrahedrons bonded to chains of sodium and water octahedrons. Most old mineral specimens of borax are chalky white d...

Bornite
(Copper Iron Sulfide) Bornite is an important copper ore mineral. It ranks up there with many of the other copper ores such as chalcocite , chalcopyrite , covellite , digenite , cuprite and tetrahedrite . As a mineral specimen, bornite is usually lacking. Good crystals are rare and thus bornite is commonly known as simply a...

Breccia
Breccias are a relatively common clastic sedimentary rock. They form in many different violent situations where host rocks are broken and not transported far from their source. These situations include any scenario in which rocks can be broken and re-accumulate to form the angular sediment. Landslides, fault zones, cryptolithic explosion even...

Brass
(Copper Zinc Alloy) Brass is not an officially recognized mineral as yet, although it has been proposed. It is not the man-made brass that is under consideration, but specimens of naturally occurring crystals of a copper nickel alloy with a formula similar to what we know as brass. These specimens are also not common, but are ex...

Brookite
(Titanium Oxide) Brookite is a polymorph with two other minerals. The minerals rutile and anatase as well as brookite all have the same chemistry, TiO 2 , but they have different structures. At higher temperatures, about 750 degrees Celsius, brookite will automatically revert to the rutile structure. Rutile is the more com...

Brucite
(Magnesium Hydroxide) Brucite is a mineral that is not often used as a mineral specimen but does have some important industrial uses. It is a minor ore of magnesium metal and a source of magnesia. It is also used as an additive in certain refractories. It is brucite's structure that is interesting. The basic structure forms sta...

Calcite
(Calcium Carbonate) < Calcite , which gets its name from `chalix` the Greek word for lime, is a most amazing and yet, most common mineral. It is one of the most common minerals on the face of the Earth, comprising about 4% by weight of the Earth's crust and is formed in many different geological environments....

Calomel
(Mercury Chloride) Calomel is a somewhat rare mineral and is never found in large quantities. It is most often a secondary mineral that forms from the alteration of cinnabar or other mercury minerals. It also is deposited from hot underground solutions. Its common habit is as coatings on other minerals. The luster is very hig...

Chalk
Chalk is a sedimentary rock of biochemical origin. It is soft, white and porous. It formed in the deep ocean far from land via the gradual accumulation of the calcite shells of coccolithophores. Layers of chalk are known that are hundreds of feet thick, indicating extremely long periods of accumulation.

Chromite
(Iron Chromium Oxide) Chromite is the most important ore of chromium from which it derives its name. Chromium is an important metal and has a wide range of industrial uses. Chromite forms in deep ultra-mafic magmas and is one of the first minerals to crystallize. It is because of this fact that chromite is found in some concent...

Chlorite
(Iron Aluminum Magnesium Silicate Hydroxide) Chlorite is a general name for several minerals that are difficult to distinguish by ordinary methods. These minerals are all apart of the Chlorite Group of minerals. The chlorites are often, but not always considered a subset of the larger silicate group, The clays . The general...

Charoite
(Hydrated Sodium Calcium Barium Strontium Silicate Hydroxide Fluoride) Charoite is an unsual mineral and of rare occurence. It is found to date in only one location: along the Chary River at Aldan in Russia. It formed from alteration of limestones by the close presences of an alkali-rich nephline syenite intrusion. The heat, pre...

Cinnabar
(Mercury Sulfide) Cinnabar is a colorful mineral that adds a unique color to the mineral color palette. Its cinnamon to scarlet red color can be very attractive. Well shaped crystals are uncommon and the twinned crystals are considered classics among collectors. The twinning in cinnabar is distinctive and forms a penetration tw...

Coal
Coal is a sedimentary rock of biochemical origin. It forms from accumulations of organic matter, likely along the edges of shallow seas and lakes or rivers. Flat swampy areas that are episodically flooded are the best candidates for coal formation. During non-flooding periods of time, thick accumulations of dead plant material pile up. As the ...

Coesite
(Silicon Dioxide) Coesite is a polymorph of quartz , meaning that it is composed of the same chemistry, SiO 2 , but has a different structure. Both quartz and coesite are polymorphs with all the members of the Quartz Group which also include cristobalite , tridymite and stishovite . Well formed crystals are very rare ...

Corundum
(Aluminum Oxide) When someone lists the most famous gemstones such as diamond , topaz , aquamarine , emerald and garnet , corundum does not usually get mentioned. However, its two varieties are sure to be on any list of gemstones. The red variety of corundum is known as ruby and all the other colors...

Comets
Comets are (traditionally) celestial bodies that show comas and/or tails. A more modern definition is any planetoid composed primarily of ices, which would boil off if the body was close enough to the Sun. Comets near or beyond Jupiter's orbit are generally stable, as water ice is unaffected by the Sun's warmth beyond about 5 au. Note that pure, ...

Copper
(Cu) Native copper (copper found in a chemically uncombined state) has been mined for centuries and now is all but depleted as an economically viable ore. Other copper minerals are far more economical to mine and purify into metallic copper that is used for wiring, electrical components, pennies and other coins, tubing and many ...

Creedite
(Hydrated Calcium Aluminum Sulfate Hydroxide Fluoride) Creedite is a rather rare sulfate found as an accessory to highly oxidized ore bodies. It can be confused with cobalt-rich adamite when its color is purple. It lacks adamite's luster, though, and adamite's dome termination is not slanted, as creedite's is. Creedite's purple ...

Cryolite
(Sodium Aluminum Fluoride) Cryolite is an uncommon mineral of very limited natural distribution. Mostly considered a one locality mineral, although there are a few other minor localities, it was only found in large quantities on the west coast of Greenland. It was used as a solvent of the aluminum rich ore, bauxite, which is ...

Crocoite
(Lead Chromate) Crocoite is a rather unusual lead mineral and can be a beautiful and colorful specimen. Crocoite provides a nice color to the mineral kingdom and is well known for its distinctive orange-red color. Its main source of quality specimens comes from the Dundas District of Tasmania, Australia. The crystals there are u...

Cubanite
(Copper Iron Sulfide) Cubanite (also known as `chalmersite`) is a rare copper mineral that does not contribute much to the supply of copper. It would not even be considered an ore of copper except that it is often interbedded with other ores of copper and so it does contribute some copper when these other ores...

Cuprite
(Copper Oxide) Cuprite has been a major ore of copper and is still mined in many places around the world. Of all the copper ores except for native copper, cuprite gives the greatest yield of copper per molecule since there is only one oxygen atom to every two copper atoms. As a mineral specimen, cuprite shows fine examples of we...

Datolite
(Calcium Boron Silicate Hydroxide) Datolite is a popular mineral among mineral collectors although it is somewhat obscure. It forms nicely faceted complex crystals. The crystals at first glance could appear to be other crystal forms such as the isometric dodecahedron or trapezohedron. However these highly symmetric crystal forms...

Diamond
(Carbon) Diamond is the ultimate gemstone, having few weaknesses and many strengths. It is well known that Diamond is the hardest substance found in nature, but few people realize that Diamond is four times harder than the next hardest natural mineral, corundum (sapphire and ruby). But even as hard as it is, it is not imper...

Dioptase
(Iron Aluminum Silicate) Dioptase is a very beautiful mineral and it is one of the few minerals that can challenge the peerlessness of emerald's deep green. Unfortunately it is rather soft (for a gemstone) and has good cleavage and therefore is not usually cut as a gemstone. The mineral specimens that dioptase produces, however,...

Diopside
(Calcium Magnesium Silicate) Diopside is an important rock forming mineral in several metamorphic and basic to ultra basic igneous rocks, also found in meteorites . Diopside is a part of an important solid solution series of the pyroxene group. The series includes the minerals hedenbergite , CaFeSi 2 O 6 , and augite , (C...

Digenite
(Copper Sulfide) Digenite is an important ore of copper, although it is not very well known even by mineral collectors. The reasons for this lack of appreciation for digenite could be due to the fact that it does not generally form good crystals, lacks brilliant colors and is easily confused with other copper sulfides. But as is...

Dolomite
(Calcium Magnesium Carbonate) Dolomite, which is named for the French mineralogist Deodat de Dolomieu , is a common sedimentary rock-forming mineral that can be found in massive beds several hundred feet thick. They are found all over the world and are quite common in sedimentary rock sequences. These rocks are called appropriat...

Dravite
(complex Sodium Magnesium Iron Boro-Aluminum Silicate) Dravite is a little known species of the Tourmaline Group. The two best-known species of tourmalines are Schorl (black, iron rich) and Elbaite (various colors and sometimes cut for gems, lithium rich). Nearly all tourmaline jewelry is elbaite. Dravite is brown, and will some...

Duftite
(Lead Calcium Copper Zinc Arsenate Hydroxide) Duftite is an oxidation product of weathered ore deposits. It is often associated with other beautiful and/or rare oxidation minerals. The formula is typically written without the calcium and zinc as these elements are not always a significant percentage of the mineral. The color o...

Edenite
(Sodium Calcium Magnesium Iron Aluminum Silicate Hydroxide) Edenite is an uncommon amphibole mineral. It is related to the more well known amphibole, hornblende . Although hornblende is no longer an official mineral, it still serves as a general name for iron, magnesium, aluminum and calcium rich amphiboles of which edenite...

Elpidite
(Hydrated Sodium Zirconium Silicate) Elpidite is another in the long list of unusual mineral that come from agpaitic pegmatite rocks. Agpaitic pegmatite intrusions are unusual igneous rocks that are high in alkaline metals (such as sodium) and poor in silica. These intrusions also contain a large number of unusual elements suc...

Elbaite
(Sodium Lithium Aluminum Boro-Silicate Hydroxide) Elbaite belongs to the group of minerals known as the Tourmalines. It is the most colorful member of this group. Elbaite is often cut as a gemstone, sliced into colorful cross-sections or simply appreciated as natural specimens by millions of rock collectors. The many varied...

Enargite
(Copper Arsenic Sulfide) Enargite is a somewhat rare copper mineral. It does not often form well shaped crystals, but there are several localities that produce some fine enargite clusters. Its crystals that form tabular to blocky to prismatic forms are often pseudohexagonal, having six sides but not six identical sides. Twinnin...

Epsomite
(Hydrated Magnesium Sulfate) Epsomite, or heptahydrite as it is known in chemistry circles, is one of only a few water soluble sulfate minerals. It is actually well known in most households as the artificially created epsom salt. Magnesium sulfate's medicinal uses were discovered from mineral waters at Epsom, England from where ...

Epidote
(Calcium Aluminum Iron Silicate Hydroxide) Epidote is a structurally complex mineral having both single silicate tetrahedrons, SiO 4 , and double silicate tetrahedrons, Si 2 O 7 . The formula of epidote could be expressed in a such a way so as to reflect this organization; Ca 2 (Al, Fe)Al 2 O(SiO 4 )(Si 2 O 7 )(OH). The two alum...

Erionite
(Hydrated Potassium Sodium Calcium Magnesium Aluminum Silicate) Erionite is one of the rarer zeolites, a popular group of minerals to collect. Erionite has been challenged as a new mineral species. It was thought to be another rare zeolite named offretite . Offretite was named first and if erionite were proven in actuality to ...

Esperite
(Calcium Lead Zinc Silicate) Esperite is one of the 70 some fluorescent minerals from Franklin and Sterling Hill, New Jersey . It will fluoresce a nice yellow color under short-wave ultraviolet light. This fluorescent color is in striking contrast to the normal color of esperite. Under normal light, esperite is white or color...

Euxenite
(Rare Earth Yttrium Niobium Tantalum Titanium Oxide) Euxenite, which is sometimes named euxenite-(Y) (the Y is for the yttrium), is a mineral that is sometimes called a `trash can mineral` . Because it will accommodate a wide variety of elements in its crystal structure, generally the elements that other minerals do no...

Euclase
(Beryllium Aluminum Silicate Hydroxide) Euclase is not a well known gemstone, but is more well known by mineral collectors. It forms well formed crystals that occasionally have enough clarity to be cut as gems. The sapphire blue and blue green colors of euclase are the typical colors of the gemstones. The crystals of euclase ar...

Fayalite
(Iron Magnesium Silicate) Fayalite is named for the Island of Fayal of the Azores. It is one of two minerals that are simply known as olivine . The other mineral is forsterite . Fayalite is the iron rich member with a pure formula of Fe₂SiO₄ . Forsterite is the magnesium rich m...

Fedorite
(Hydrated Sodium Potassium Calcium Silicate Fluoride Chloride Hydroxide) Fedorite is a rare alkali mineral from the famous Kola Peninsula , of Russia. It is named for one of the founders of modern crystallography, Russian scientist Evgraf Stepanovich Fedorov. It forms nice `mica` like crystals that can have an attractive ligh...

Fluorite
(Calcium Fluoride) Fluorite is a mineral with a veritable bouquet of brilliant colors . Fluorite is well known and prized for its glassy luster and rich variety of colors. The range of common colors for fluorite starting from the hallmark color purple, then blue, green, yellow, colorless, brown, pink, black and reddish or...

Gahnite
(Zinc Aluminum Oxide) Gahnite is one of the rarer members of the Spinel Group of minerals, an important group of oxides. It is named after Swedish chemist L. G. Gahn, who discovered manganese. Gahnite forms in some granitic pegmatites, zinc deposits and in skarns, a special type of contact metamorphic rock. Gahnite produces ...

Gaspeite
(Nickel Magnesium Iron Carbonate) Gaspeite is considered a rare mineral, being found in only a few localities, but it is becoming a popular mineral in the semi-precious stone markets. It is being used as a cabochon in sterling silver jewelry with such notable minerals and material as turquoise , malachite , azurite , onyx ...

Galena
(Lead Sulfide) Galena is a common and popular mineral for rock hounds. Its characteristic cubes, distinctive cleavage and high density make it easy to identify and a favorite in high school geology labs. The structure of Galena is identical to that of halite, NaCl. The two minerals have the same crystal shapes, symmetry and clea...

Geodes
Geodes are technically sedimentary rocks, since they are theresult of the action of water. Geodes are formed when cavities in a hostrock (which may be sedimentary or igneous) become lined with a durable mineral, often a variety of quartz. The term geode usually refers to rounded nodules with hollow centersSome sources define a geode ...

Gibbsite
(Aluminum Hydroxide) Gibbsite is an important ore of aluminum and is one of three minerals that make up the rock Bauxite. Bauxite is often thought of as a mineral but is really a rock composed of aluminum oxide and hydroxide minerals such as gibbsite, boehmite , AlO(OH) and diaspore , HAlO 2 , as well as clays , silt and i...

Goethite
(Hydrated Iron Oxide) Goethite has had a reputation for making rather uninteresting, dull and `dirty` mineral specimens. This is definitely not true of many of the fine specimens available to collectors today. Some good pieces show splendid radiating clusters of deep black crystals. Massive stalactitic forms show rainbows of irr...

Graemite
(Hydrated Copper Tellurite) Graemite is a very rare tellurium mineral. Its type locality is the Cole Shaft, Bisbee, Arizona . Graemite joins a list of special minerals that were first discovered from this great mineral locality. Other type minerals from Bisbee include henryite , kiddcreekite , spangolite , teineite , shattuck...

Graphite
(Carbon) Graphite is a polymorph of the element carbon. diamond is another polymorph. The two share the same chemistry, carbon, but have very different structures and very different properties. ·Diamond is the hardest mineral known to man, Graphite is one of the softest. ·Diamond is an excellent elec...

Granite
(Igneous Intrusive Rock) Granite is possibly the most common igneous rock type known to the general public. Granite, which is named for its `granular` or phaneritic texture, has crystals that tend to be easily seen, although they are generally small. It is a rock that has been used for centuries for many different purpo...

Gyrolite
(Hydrated Calcium Silicate Hydroxide) Gyrolite often forms nodular aggregates. These aggregates can appear glassy, dull or even fiberous. Unlike other similar looking minerals (such as prehnite or smithsonite ), gyrolite usually forms individual nodules as opposed to botryoidal or crustal growths. The aggregate nodules can ofte...

Gypsum
(Hydrated Calcium Sulfate) Gypsum is one of the more common minerals in sedimentary environments. It is a major rock forming mineral that produces massive beds, usually from precipitation out of highly saline waters. Since it forms easily from saline water, gypsum can have many inclusions of other minerals and even trapped bubbl...

Hanksite
(Sodium Potassium Sulfate Carbonate Chloride) Hanksite is an unusual mineral mostly because of its formula. It is one of only a handful of minerals that contain both carbonate and sulfate ion groups. This brings up the question: to what mineral class does it belong? Some mineral references place it in the carbonates while others...

Halite
(Sodium Chloride) Halite , better known as rock salt, can easily be distinguished by its taste. Since taste is an important property of salt, there is a right way to taste a specimen of halite (or an unknown mineral that is similar to halite) and a wrong way. The right way is to first lick your index finger, rub it against the ...

Hematite
(Iron Oxide) Hematite has several varieties, each with their own unique names. Hematite Rose is a circular arrangement of bladed crystals giving the appearance of the flower of a rose. Tiger Iron is a sedimentary deposit of approximately 2.2 billion years old that consists of alternating layers of silver gray hematite a...

Hessite
(Silver Telluride) Hessite is named after the nineteenth century Swiss chemist and Professor of St. Petersburg Mining Institute, Germain Henry Hess. He was the first to analyze specimens of this mineral, some of which were recovered by Gustav Rose in 1829. A synonym of hessite is `silver telluride` which is ch...

Hopeite
(Hydrated Zinc Phosphate) Hopeite is a rare phosphate mineral but is popular among collectors of rare minerals. It forms typically well shaped crystals that are often associated with colorful minerals like lazulite , another phosphate mineral. Hopeite is dimorphous with the mineral parahopeite . The two have the exact sam...

Humite
(Magnesium Iron Silicate Fluoride Hydroxide) Humite is the namesake member of the Humite Group of minerals. Members of the Humite Group are noted for having a mixture of silicate layers and oxide layers in their structures. The silicate layers have the same structure as olivine. The oxide layers have the same structure as ...

Ice
(Hydrogen Oxide) SNOWFLAKES Simple Prisms Stellar Plates Sectored Plates Stellar Dendrites Fernlike Stellar Dendrites Hollow Columns Needles Capped Columns Double Plates Split Plates and Stars Triangular Crystals 12-Sided Snowflakes Bullet Rosettes Radiating Dendrites Rimed Crystals

Igneous Rocks
Igneous rocks are one of the three major rock types and are basically rocks that solidified from magma. Magma is the term for liquid or melted rock and is usually quite hot. After all, the term igneous comes from the Latin word for `of fire`. Most people have seen pictures or video of magma that flows out of a volcano. When m...

Ilmenite
(Iron Titanium Oxide) Ilmenite is an economically important and interesting mineral. It is named for its place of discovery (such places are called type localities) at Ilmen Lake in the Ilmen Mountains, Miask in the southern portion of the Ural Mountains of Russia. Ilmenite forms as a primary mineral in maf...