This is the yellow-greenish ophicalcite cabochon. Dimensions: 2.2 x 0.8 x 0.1″ (5.5 x 2.1 x 0.3cm). Weight – 0.2oz (6 grams). Origin: Russia, Siberia.
Some information about ophicalcite:
Ophicalcite is a serpentinite breccia popular since ancient times as a decorative facing stone. It is a dark, dull green, white-mottled (or white-veined) serpentine, mixed with calcite, dolomite, or magnesite, which takes a high polish. It is sometimes classed, erroneously, as a variety of marble.
Non-brecciated varieties of a very similar serpentinite, sometimes also called “verd antique”, have been quarried at Victorville, California; Cardiff, Maryland; and Rochester in Addison County, Vermont.