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Figure 1. An 11.68 ct treated phantom opal in which the phantom structure appeared during experiments with various solutions. The sample is shown under daylight through the dome (left) and under halogen lighting through the bottom (right). Photos by Le Ngoc Nang.

A New Treatment: Creating Phantom Structure in Opal

Le Ngoc Nang and Pham Minh Tien, August 4, 2023

A newly developed treatment creates a phantom structure in opal visually similar to natural phantom opal.

Figure 1. Greenland’s rubies are characterized by abundant twinning planes. The twinning planes are not altered by the treatment at a larger scale, but features associated with the twinning can be significantly affected by heating. Photo by S. Wongchacree; field of view 14.40 mm.

Characteristics of Treated Rubies from Greenland

Martin Viala, Wim Vertriest, Charuwan Khowpong, and Suwasan Wongchacree, August 4, 2023

An overview of the treatment process of ruby and pink sapphire from Greenland and its effect on inclusion scenes and chemistry.

DiamondView imaging of the pavilion facets for this HPHT-treated natural diamond shows graining and zoning that resemble those of a laboratory-grown CVD diamond with HPHT treatment. The inset shows the DiamondView image of an HPHT-treated CVD-grown diamond. Images by Jemini Sawant.

Natural Diamond with CVD-Like Fluorescence Pattern

Manisha Bhoir and Shoko Odake, August 4, 2023

Examination of a natural diamond reveals graining and zoning that resemble those of a laboratory-grown CVD diamond.

Green Diamond Treated with Radioactive Salt

Marzena Nazz, March 29, 2013

The stone owes all of its green color to these shallow radiation stains.

Three CVD Synthetic Diamonds Submitted to Mumbai Laboratory

Ulrika D’Haenens-Johansson, March 29, 2013

The gemological and spectroscopic characteristics of these type IIa synthetic diamonds suggested that they experienced different growth and/or treatment histories.

Large HPHT-Treated Fancy Pink Diamond

Kyaw Soe Moe, March 29, 2013

The New York lab encountered another large HPHT-treated diamond that showed stronger pink coloration.

Article

Summer 2023 G&G Available Now

Erica Zaidman, August 4, 2023

An overview of the Summer 2023 Gems & Gemology content.

Figure 1. Suite of faceted nickel-diffused spinel (0.67–1.01 ct) showing a range of color from blue to bluish green. Photo by Aaron Palke and Diego Sanchez.

Color Modification of Spinel by Nickel Diffusion: A New Treatment

Michael Jollands, Abadie Ludlam, Aaron C. Palke, Wim Vertriest, Shiyun Jin, Pamela Cevallos, Sarah Arden, Elina Myagkaya, Ulrika D’Haenens-Johannson, Vararut Weeramongkhonlert, and Ziyin Sun, August 4, 2023

Reports on a newly discovered treatment process for producing a deep blue color in natural spinel and proposes identification criteria.

Nickel-Diffused Spinel, Vietnamese Augite, Brown Mammoth Ivory, and More…

Duncan Pay, August 4, 2023

An overview of the Summer 2023 Gems & Gemology content.

Figure 1. Part of the suite of sapphires studied for this project (weighing 0.23–1.41 ct). Photo by Sasithorn Engniwat; courtesy of Greenland Ruby.

Color Study of Fancy Sapphire from Greenland

Wim Vertriest, Charuwan Khowpong, Polthep Sakpanich, and Martin Viala, May 23, 2023

The Bangkok laboratory identifies the chromophores responsible for the fancy colors observed in treated sapphire from Aappaluttoq, Greenland.

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