1) Ammonium mineral 2) Phosphate mineral 
Struvite (magnesium ammonium phosphate) is a phosphate mineral with formula: NH4MgPO4·6H2O. Struvite crystallizes in the orthorhombic system as white to yellowish or brownish-white pyramidal crystals or in platey mica-like forms. It is a soft mineral with Mohs hardness of 1.5 to 2 and has a low specific gravity of 1.7. It is sparingly soluble in ...
• (n.) A crystalline mineral found in guano. It is a hydrous phosphate of magnesia and ammonia.
A type of crystal found in the urine of normal cats. High quantities of crystals can cause signs of bladder disease accompanied by problems with urination. Stones, or calculi, can form if the concentration of crystals is high enough and this can lead to blockage of the urinary tract, requiring surgical intervention.
Struv'ite noun [ After the Russian minister Von Struve .] (Min.) A crystalline mineral found in guano. It is a hydrous phosphate of magnesia and ammonia. 
Type: Term Pronunciation: strū′vīt Definitions: 1. The hexahydrate of magnesium ammonium phosphate; found in some renal calculi.
Ammonium magnesium phosphate