Dendritic Opal 6mm Hexagon - 15-16 Inch R1526 The yellowish colors of heliodor

The yellowish colors of heliodor are usually caused by small amounts of iron within the mineral's crystal structure

microcrystalline form of Quartz

Blue Tourmaline ranges in color from green to blue to yellow to green with black

which is itself a form of Muscovite

discovered a way to improve the quality of turquoise in the 1980's

Dendritic Opal 6mm Hexagon - 15-16 Inch R1526 The yellowish colors of heliodorThis variety of opal is named "dendritic" for the small inclusions within it that resemble moss or ferns. These inclusions consist of iron, manganese and other metallic oxides captured during the forming of the rock. Opals are hydrated amorphous forms of silica, created when silica hardens within the fissures of other stones.