COLORED STONES AND ORGANIC MATERIALS

Rubies from Longido,Tanzania,were investigated by standard gemological testing and laser ablation inductively coupled plasma mass spectrometry.Microscopic observations revealed dense needle-like and triangular inclusions,distinct growth lines,and color banding as typical inclusions.

Trapiche emeralds are usually found in Colombia. Recently the authors received six emeralds reportedly from Swat Valley, Pakistan.

PHT (“HPHT”) treat- ment in sapphire has been a controversial topic the last few years. Recently, Guild Gem Laboratories in Shenzhen re- ceived a 7.11 ct blue sapphire for identification. The refractive index of 1.762–1.770 and hydrostatic specific gravity of 4.00 confirmed the stone’s identity.