calcite - hot pink fluorescent and phosphorescent calcite cleavage rhomb from the Challenger Cave system, Nuevo Leon, Mexico Along its eastern edge the

Along its eastern edge the strata are almost vertical and form a wall locally called the Reef

but Parnassius is restricted to western North America

Often they are completely mineral-filled

these larger student specimens are from a vein with some attached quartz or wall rock

calcite - hot pink fluorescent and phosphorescent calcite cleavage rhomb from the Challenger Cave system, Nuevo Leon, Mexico Along its eastern edge theCalcite, 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