Copy of `Rocks for Kids - Geology terms`

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Rocks for Kids - Geology terms Category: Sciences > Geology Date & country: 02/06/2011, UK Words: 35

alloy
a combination of metals to make a new metal compund

botryoidal
shaped like a bunch of grapes, e.g. botryoidal chalcedony

book
a stack of thin, flat crystals that form a "book", e.g. book of mica

breccia
means angular, refers to a type of rock where angular pieces of rocks are

button
a small cluster or plate of crystals, e.g. amethyst button

common names
when rocks and minerals are known by names that are descriptive, not scientific

crystal habit
the form that the crystals of a mineral take when they have enough space and time to grow properly

cryptocrystalline
when the crystals are so small, they cannot be seen except with a microscope

dendritic
tree-like

fibrous
used to describe mineral crystals that are long and thin and look like fibers

geode
a round rock that has a hard "skin" on the outside and that usually is hollow on the inside, often lined or filled with mineral crystals, most common type is the quartz geodes

gemstone
a precious or semi-precious stone that is used in jewellery, often clear or gemmy

gemmy
clear or transparent like a gem, used to describe transparency of a mineral

host rock
this is the rock that surrounds a mineral specimen, the matrix

lapidary
the craft of forming shapes, items, gemstones from rocks & minerals

matrix
the rock that mineral specimens are found in are called the matrix or host rock

massive
not a crystal, a piece of a mineral with no particular shape

nodule
rounded, spherical or kidney shaped rock or mineral, often with a "skin"; because it is harder than the surrounding rock it is in, it weathers out intact; e.g. pyrite nodule

opaque
no light can pass through it, massive pieces of most minerals are opaque, almost all metallic minerals are opaque

ornamental stone
a rock or stone that is used for decoration, as an ornament - such as for lamps, book ends, wall and floor tile, tables, sculptures - usually because of its beautiful colour or pattern

perfect cleavage
some minerals break easily into flat pieces and this is called perfect cleavage, cleavage means "to come apart"

prismatic
crystal shaped like a prism with flat sides and a pointy termination or end, e.g. quartz crystal

rhomb
looks like a squished box, short form for rhombohedral, resembling a prism with six four-sided faces

rockhound
someone who collects rocks and minerals

road cut
a road cut is where the rock has been cut to let the road go through

schiller
when the light hits some minerals, they almost glow and show a bronzy or peacock color that changes with how the light hits the surface, a deep luster, iridescent

sedimentary
rocks that are formed when layers of sand, clay & bits of rock are laid down by water & turned to rock, often contain fossils

specimen
a term used to refer to a mineral or rock sample, a piece one is studying or using as an example

striations
parallel lines on the face of a crystal

termination
the end of a crystal that has grown properly, can be rounded, flat or pointed

transparent
clear, light can pass through, e.g. a piece of clear glass

transparency
a physical characteristic of minerals, used to describe how much light can pass through a specimen

translucent
some light can pass through it but it is not clear; many minerals that are opaque can be made to appear translucent if a thin enough slice is cut off & light shone through it; e.g. wax paper

vitreous
shiny like glass

vug
a hollow space in a rock where crystals often grow, e.g. Herkimer diamond in a vug