calcite - cool pink fluorescent and phosphorescent calcite - cleavage rhomb from the Challenger Cave system, Nuevo Leon, Mexico The field photo shows the

The field photo shows the entrance to the short mine adit where a vein of tremolite occurs in the ceiling

Others in Eueides are palatable but protected by their color pattern

The pen is 5" long

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

This medium-grained sandstone is composed primarily of quartz with feldspar and some biotite

calcite - cool pink fluorescent and phosphorescent calcite - cleavage rhomb from the Challenger Cave system, Nuevo Leon, Mexico The field photo shows 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