calcite - hot pink fluorescent and phosphorescent calcite cleavage rhomb from the Challenger Cave system, Nuevo Leon, Mexico If treated with a combination

If treated with  a combination of sulfuric and phosphoric acids

but Parnassius is restricted to western North America

The Seitz plates are spectacular examples of scientific illustration and printing from the early 1900s

usually as a semi-precious stone or decorative rock

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 If treated with a combinationCalcite, 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