Scapolite

Scapolite is the name for a group of closely related tectosilicate minerals that form a series between sodium-rich and calcium-rich end members. It is valued by collectors and gem cutters for its long prismatic crystals and attractive colours.

Identifying scapolite

Scapolite is moderately hard (5.5–6) with a glassy lustre and good cleavage, occurring in white, grey, yellow, violet and pink. Gem scapolite can be transparent and is sometimes cut to show a cat's-eye effect; many scapolites fluoresce under ultraviolet light.

Where it is found

Scapolite forms in metamorphic rocks, especially marbles, and in some skarns and pegmatites. Fine crystals and gem material come from Brazil, Madagascar, Tanzania, Myanmar and Canada (the Grenville marbles of Ontario and Quebec).