This is the bluish-green apatite crystal with yellow calcite. Dimensions: 2.6 x 2.4 x 1.8″ (6.7 x 6 x 4.6cm). Weight – 9.3oz (263 grams). Origin: Russia, Siberia.
Some information about apatite:
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite and chlorapatite, named for high concentrations of OH, F and Cl ions, respectively, in the crystal.
The mineral named apatite by the German geologist Abraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August Rammelsberg. Apatite often mistaken for other minerals. This tendency reflected in the mineral’s name, which derived from the Greek word, which means to deceive.
Apatite is the defining mineral for 5 on the Mohs scale. It can be distinguished in the field from beryl and tourmaline by its relative softness. It is often fluorescent under ultraviolet light.