rare clear rock crystal sphere with grown-in green and brown-black tourmaline crystals

A rare clear rock crystal sphere from Madagascar, with included green and brown-black tourmaline crystals. Two tourmaline varieties in one piece: green verdelite and black schorl.

Rock crystal (SiO₂) and tourmaline (borosilicate mineral group) grew together in pegmatitic cavities. The two tourmaline colorations show different trace element configurations: schorl (Na, Fe-bearing) is black, verdelite (Mg/Cr-bearing) is green.

Such multicolored tourmaline-in-quartz specimens are classified as premium gemmological pieces in the collector's trade. The combination of two tourmaline varieties in a clear quartz documents complex deposit conditions with oscillating solution chemistry.

Madagascar provides such multi-component quartz from the pegmatite deposits of the Vakinankaratra region. The high clarity of the quartz background allows both tourmaline varieties to be visually clearly distinguished.

A collector's item with a gemmologically valuable multi-mineral composition.