Canasite: Gemstone Information

Canasite is Na3K3Ca5Si12O30(OH,F)4 and occurs as greenish yellow granular blocks of the monoclinic system with hardness 5–6, perfect cleavage in two directions and SG 2.70. The grains are usually twinned.The RI for the alpha, beta and gamma rays is 1.534, 1.538 and 1.543,biaxial negative with birefringence 0.009. Canasite occurs in pegmatites in a differentiated alkalic massif at Khibiny, Russia. A purplish material is sometimes referred to as ‘canasite’ or ‘stichtite’ (q.v.). Work on differentiation continues.