Common examples include calcite, quartz, topaz, beryl, tourmaline and fluorite, among others.
en.wikipedia.org The disks were made of hard calcite, which has formed most of today's limestone.
en.wikipedia.org There are also mini-formations including floating calcite crystals, over twenty nests of cave pearls, and delicate fern-like crystals less than long.
en.wikipedia.org The test, (or shell), is of translucent, perforate, optically radial calcite.
en.wikipedia.org Moreover, the calcite alabaster, being a carbonate, effervesces upon being touched with hydrochloric acid, whereas the gypsum alabaster, when thus treated, remains practically unaffected.
en.wikipedia.org