corundum, USA.12, Montana.12, Yogo Gulch, assembled stones.8, gems

Liddicoat reports an unusual assembled stone examined by the Gem Trade Laboratory in Los Angeles consisting of Montana sapphire used in a doublet. The brief laboratory note describes the construction and appearance of the composite and the features that permit its recognition under gemological examination. The specimen illustrates the variety of assembled stones encountered in the gem trade and emphasizes the importance of careful examination for junction planes and other evidence of composite construction when identifying apparently natural sapphire.