Yellow Calcite 10mm Round A Grade - 15-16 Inch bicone_beads It sometimes features dark brown

It sometimes features dark brown to black dendritic inclusions that branch like tiny tree limbs through the stone

As a Serpentine

The two most popular classes of Australian Opal are Black Opal mined in Lightning Ridge and Fire Opal

are more special than most

Yellow Calcite 10mm Round A Grade - 15-16 Inch bicone_beads It sometimes features dark brownCalcite is a rock forming mineral that is extremely common and found throughout the world in sedimentary, metamorphic, and igneous rocks. Calcite is the principal constituent of limestone and marble. These rocks are extremely common and make up a significant portion of Earth's crust.