Feature Gems & Gemology, Summer 1983, Vol. 19, No. 2

Investigation of a Cat's-Eye Scapolite from Sri Lanka

A cut gemstone with intense chatoyancy that originated from Sri Lanka was determined to be a member of the scapolite solid-solution series. Indices of refraction and unit-cell dimensions were found as ω = 1.583, ε = 1.553 and a = 12.169, c = 7.569 Aº respectively; a meionite content of 69% was established by microprobe analysis. The chatoyancy is caused by needle-like inclusions with an orientation parallel to the c-axis of the scapolite host crystal. Microprobe analysis of these needles showed them to be pyrrhotite.