Thortveitite: a new gemstone

A water-worn pebble of good clarity purchased in Bangkok started the quest that identifi ed this as gem-quality thortveitite, a scandium yttrium silicate. A faceted stone and a cleavage frag- ment, both from the original pebble, have been tested. Results from standard gemmological tests on the faceted stone did not match those from any known gemstone. The stone and fragment were subsequently identifi ed as high-scandium thortveitite. The unusual chemistry indicates a possible synthetic origin; however, a natural origin is suggested by the presence of three-phase inclusions in a planar array (feather) within the faceted stone.

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