Fancy Deep Brown-Orange CVD Synthetic Diamond
A CVD-grown diamond shows an unexpected treatment-caused color.
Fracture-Filled Diamond with "Rainbow" Flash Effect
The material used to fill a large fracture in a diamond yields an unexpected iridescence under two different illuminations.
Turquoise with Simulated Matrix
A turquoise bead is found to have an artificial pyrite and resin matrix.
Hydrophane Opal Treatment
An opal rough is immersed in water and treated with oil and Opticon to observe effects on transparency and play-of-color.
Very Large Artificially Irradiated Yellow Diamond
Examination of a 59.88 ct irradiated yellow diamond, one of the largest irradiated diamonds identified by GIA.
Treated Pink Type IIa Diamond Colored by Red Luminescence
A type IIa color-treated diamond was graded as Fancy brown-pink under daylight conditions and Fancy purplish gray under incandescent lighting, a color change that resulted from HPHT annealing and irradiation.
Evidence of Focused Beam Irradiation in Treated Pink Diamond
DiamondView imaging and photoluminescence spectroscopy offered evidence of focused beam irradiation in a pink diamond.
Lead Glass–Filled Black Star Sapphire
The first example of a lead glass–filled black star sapphire examined at GIA’s New York laboratory.
Treated Red and Green HPHT Synthetic Diamonds
Two treated synthetic diamonds, a Fancy red and a Fancy Vivid yellowish green, showed strikingly vibrant colors.
Unique Drilled Emerald
An emerald with drill holes containing a resinous material is seen in the New York lab.