calcite - cool pink fluorescent and phosphorescent calcite - cleavage rhomb from the Challenger Cave system, Nuevo Leon, Mexico sometimes with a hollow center

sometimes with a hollow center

though these specimens are not well cemented and should be handled gently

The name muscovite was first used in 1794 in A System of Mineralogy by Johann Gottfried Schmeisser

The mineral was called "cyanite" by mineralogists using the French spelling

Locally it is poorly to moderately well cemented with silica cement

calcite - cool pink fluorescent and phosphorescent calcite - cleavage rhomb from the Challenger Cave system, Nuevo Leon, Mexico sometimes with a hollow centerCalcite, CaCO3, is an extremely common rock forming mineral. In pegmatites it forms large masses and it makes up some limestones almost entirely. It has a large variety of crystal forms, but these do not include the rhombus shaped pieces that are sold as calcite crystals. The rhombs are produced by cleaving calcite in three directions between rows of atoms. When calcite is free of impurities and is optically clear, it exhibits double refraction. When