Ancient forms of this material have been found to contain tetravalent uranium. Glendonite is an example of this material which retains the shape of ikatite, which is itself a 
Ancient forms of this material have been found to contain tetravalent uranium. Glendonite is an example of this material which retains the shape of ikatite, which is itself a hydrated form of this mineral. Vaterite and aragonite are polymorphs of this substance, which is used as the standard for 3 on Mohs hardness scale, and exhibits perfect rhombohedral cleavage along 3 planes. A special example of it found in standing waters in caves is called Dogtooth spar, and it is also found in marble and limestone. For 10 points, identify this mineral that is mostly made of calcium carbonate.
Ancient forms of this material have been found to contain tetravalent uranium.
calcite