Article Search Results

Amber and plastic reactions to illumination.

Plastic Amber Imitation in a Rosary

Nazar Ahmed Ambalathveettil, Mohamed Karam, and Sutas Singbamroong, May 8, 2017

Examination reveals both amber and Bakelite plastic beads in a rosary submitted for identification.

Natural-color yellow sapphires with FTIR features of Punsiri-treated sapphire

“Punsiri”-type FTIR Spectral Features in Natural Yellow Sapphires

Supharart Sangsawong, Vincent Pardieu, Victoria Raynaud, and Sasithorn Engniwat, November 7, 2016

Testing of natural-colour yellow sapphires from Australia and Thailand with the FTIR features of “Punsiri” heat-treated material.

Purple pyrope-almandine garnets from Manica Province, Mozambique

Purple Pyrope-Almandine Garnet From Mozambique

Supharart Sangsawong, Victoria Raynaud, and Vincent Pardieu, November 7, 2016

Analysis of attractive purple garnets from a new deposit in central Mozambique.

Musgravite from Myanmar

Nathan Renfro

Two small, near-colourless stones reportedly from Myanmar (0.11 and 0.24 ct; figure 1) were recently loaned to GIA for examination for identification.

Blue cat's-eye apatite

Tao Hsu

Deep blue apatite with a cat’s-eye effect, however, is very rare.

Demantoid garnet fossil pseudomorphs

Emmanuel Fritsch, Julien Raoul, Benjamin Rondeau, and Olivier Segura, January 31, 2014

In these two extremely rare specimens, demantoid garnet has replaced coral and gastropod fossils.

Faceted wurtzite from Tanzania

Jaroslav Hyršl, January 31, 2014

The rarity and value of faceted wurtzites from Tanzania are sure to draw the attention of gem collectors.

Bangle of polymer-impregnated aventurine quartz

Polymer-Impregnated Aventurine Quartz, a New Imitation of “Ice Jade”

Larry Tai-An Lai, April 30, 2014

A bangle, thought to be jadeite jade, is revealed by laboratory testing to be polymer-impregnated aventurine quartz.

Coated Fire Opal in the Chinese Market

Wen Han, Taijin Lu, Hua Chen, and Jian Zhang, October 31, 2014

An investigation of a coated fire opal recently found in the Chinese market.

Bright yellow diamonds from Sierra Leone

James Shigley and Christopher M. Breeding, January 31, 2014

Examination of strongly yellow diamonds from the Zimmi area of Sierra Leone revealed graphitised feather inclusions.

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