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.

In recent years, Ethiopian opals have rapidly flooded into the jewelry market, sparking widespread research interest. In this paper, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and ultraviolet-visible spectrophotometry were used to conduct a spectroscopic analysis of Hydrophane opals from the Wollo region in Ethiopia, and they were compared with black opals, white opals, and water opals. In addition, the water absorbency was demonstrated through water immersion experiments. The results show that the infrared absorption peak near 1098 cm⁻¹ and the relatively strong absorption peak near 970 nm are effective bases for determining Hydrophane opals.

Tremolite is a member of the amphibole group in silicate minerals with the chemical formula of Ca2Mg5[(OH)Si4O11]2. The crystals are generally arranged in radial, fibrous or slender prismatic shapes.