News from Research

"A New Dyed Purple Opal"
Nathan Renfro and Shane F. McClure
GIA Laboratory, Carlsbad

Examination of a group of opals with an unusual bright purple bodycolor and strong play-of-color. Download article.

A compilation of ongoing research into red feldspar and its sources around the world, as well as the detection of various color treatment processes. 

Download Part 1 (Sept. 9, 2009)
Download Part 2 (Aug. 1, 2011)

"LA-ICP-MS Analysis as a Tool for Separating Natural and Synthetic Malachite"
Christopher M. Breeding and Andy Shen
GIA Laboratory, Carlsbad

The LA-ICP-MS technique is applied in an attempt to separate natural and synthetic malachite on the basis of trace-element chemistry. Download article.

"Using the DiamondView to Detect Irradiation-Induced Defects in a Brown-Orange Diamond"
Sally Chan and Paul Johnson
GIA Laboratory, New York

Reports on a diamond that displayed strikingly different fluorescence behavior between the table and pavilion facets, a clear indication of irradiation. Download article.

"FAPFH/GFF Treated Ruby from Mozambique:
A Preliminary Report"
Vincent Pardieu, Nick Sturman, Sudarat Saesaew,
Garry Du Toit, and Kamolwan Thirangoon
GIA Laboratory, Bangkok

Reports on rubies from the Montepuez area of Mozambique that have been heated at high temperature using a “flux‐assisted partial‐fissure‐healed” (FAPFH) and glass‐fissure‐filled (GFF). Download article.

"Lead Glass-Filled Star Rubies Reportedly from Madagascar" 
Vincent Pardieu, Pantaree Lomthong and Nick Sturman
GIA Laboratory, Bangkok

A preliminary examination of 34 star rubies, supposedly from Madagascar, that had had been clarity-enhanced with a lead-glass filler. Includes a comparison with star rubies from other deposits. Download article.

"Expedition Report to the Ruby Mining Sites in Northern Mozambique (Niassa and Cabo Delgado Provinces)"
Vincent Pardieu* with Stephane Jacquat, Jean Baptiste Senoble, Lou Pierre Bryl, Richard W. Hughes, and Mark Smith
* GIA Laboratory, Bangkok

Reports on an ongoing GIA field expedition to the various ruby mining areas of northern Mozambique. Download article.

"Analysis of HPHT-Treated Diamonds Using Fluorescence Observations"
Sally Eaton-Magaña and Karen Chadwick
GIA Laboratory, Carlsbad

Evaluates a potential method of visually identifying HPHT-treated diamonds using microscopy to observe intense fluorescence at the facet edges and junctions. Download article.

"The Microradiographic Structures of Non-Bead Cultured Pearls"
Nick Sturman
GIA Laboratory, Bangkok

Examines the X-ray structures of non-bead cultured pearls, including "Keshi" pearls, and the criteria used to identify them. Download article.

"Coesite Inclusions: Microbarometers in Diamond"
Ren Lu
GIA Laboratory, New York

Microscopic and spectroscopic examination  of a suite of pink diamonds revealed inclusions of the mineral coesite, offering insight into their chemical and physical history. Download article. 

"Study of New Method for Adding Fire to Diamonds"
Al Gilbertson
GIA Laboratory, Carlsbad

Previews a forthcoming study on the placement of diffraction gratings on a diamond's surface to increase the appearance of fire. Download article.

"Silicon Detectability in Corundum Using LA-ICP-QMS (Laser Ablation–Inductively Coupled Plasma–Quadrupole Mass Spectrometry)"
Andy H. Shen
GIA Laboratory, Carlsbad

Presents details and a word of caution on detecting silicon in corundum, which has implications for color in Be-diffused sapphires. Download article.

Comments on: “A Question Concerning Heat–Treated Blue Sapphires," by Koivula and Inns
John L. Emmett
Crystal Chemistry, Brush Prairie, Washington

A response to the July 24 "News from Research" entry on gemological characteristics related to certain heated blue sapphires. Download article.

"Using LA-ICP-MS Analysis for the Separation of Natural and Synthetic Amethyst and Citrine"
Christopher M. Breeding
GIA Laboratory, Carlsbad

An exploratory investigation of the value of laser ablation–inductively coupled plasma–mass spectroscopy in identifying natural and synthetic quartz. Download article. 

"A Question Concerning Heat-Treated Blue Sapphires"
John I. Koivula and Alethea Inns
GIA Laboratory, Carlsbad

Presents a pattern of gemological characteristics related to certain heat-treated blue sapphires. Download article. Also, download the comments on this article by John Emmett.

"Photoluminescence Features of Carbonado Diamonds"
Wuyi Wang, Ren Lu, and Tom Moses
GIA Laboratory, New York

Reports on the photoluminescence features of three faceted carbonado diamonds and proposes some constraints on the geologic conditions of their formation. Download article.

"Natural-Colored Chrome Chalcedony Identified Using Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry (LA-ICP-MS)"
Andy Shen
GIA Laboratory, Carlsbad

A report on the use of trace-element LA-ICP-MS analysis to determine the coloring agent (natural or artificial) of chrome chalcedony. Download article. 

"Beryllium-Treated Blue Sapphire: Continuing Market Observations and Update"
 Garry DuToit, Jitlapit Thanachakaphad and Kenneth Scarratt
GIA Laboratory, Bangkok

An update on the market presence of beryllium-treated blue sapphires and their identifying characteristics. Two large samples (22 and 53 ct) are also described. Download article.

"Concise Field Report: Melos and Their Pearls in Vietnam"
Vincent Pardieu
GIA Laboratory, Bangkok

Reports on a May–June 2009 Melo pearl expedition to Cat Ba Island, off the coast of northern Vietnam. Download article.

"Treated Fancy Red Diamond"
Paul Johnson and Christopher M. Breeding
GIA Laboratory, New York and Carlsbad

Examines a 2.14 ct oval-cut diamond, graded as Fancy red, whose red color was produced through a combination of high-presssure, high-temperature (HPHT) treatment and irradiation plus annealing. Download article.

"A Large Naturally Colored Natural Blister Pearl"
Nick Sturman
GIA Laboratory, Bangkok

Details the examination of a 29.95 x 23.16 x 19.34 mm dark violetish gray blister pearl using X-radiography, magnification, and other techniques. Download article. 

"Corundum C-Axis Device for Sample Preparation"
Timothy Thomas
GIA Laboratory

Describes a new tool tool and method for finding the optical c-axis of corundum and preserving it through the grinding and polishing process. Download article.

"Effects of Heating and Copper Diffusion on Feldspar: An Ongoing Research"
Kamolwan Thirangoon
GIA Laboratory, Bangkok

Presents the results of heat treatment and copper-diffusion experiments on light yellow feldspar from the United States, Mexico, and China. Download article.

"Micro-Magma Chambers in Natural Rubies and Sapphires:
The Behavior of Some Mineral Inclusions in Corundum At High Temperatures"
John I. Koivula
GIA Laboratory, Carlsbad

Examines the effect that heat-treating has on preexisting solid inclusions, and how to distinguish these damaged inclusions from the results of flux healing or other forms of artificial infilling. Download article.

"Concise Field Report, Volume 1: Pailin, Cambodia"
Vincent Pardieu
GIA Laboratory, Bangkok

A summary of two expeditions to the important ruby and sapphire deposits of Pailin, in late 2008 and early 2009. Includes a look at rough and faceted samples. Download article.

"Sapphires Reportedly from the Batakundi/Basil Area"
Vincent Pardieu, Kamolwan Thirangoon, Pantaree Lomthong, Sudarat Saeseaw, Jitlapit Thanachakaphad, and Gary Du Toit
GIA Laboratory, Bangkok

A preliminary examination and  comparison with rubies and pink sapphires from other deposits in Central Asia. Download article.

"CVD-Grown Pink Diamonds"
Wuyi Wang
GIA Laboratory, New York

An examination of seven CVD synthetic diamonds with an attractive pink color. Download article.

"The Role of Secondary Fluid Inclusions in Detecting Heat Treatment"
John I. Koivula
GIA Laboratory, Carlsbad

Examines what happens to secondary fluid inclusions (also known as "fingerprints") at extremely  high temperatures, and their usefulness in detecting heat treatment. Download article.

"A Discussion of Ruby-Glass Composites"
Ken Scarratt
GIA Laboratory, Bangkok

Describes several rubies treated with glass and experiments on rubies treated with glass, demonstrating that the stones are bonded together by the glass.  Download article.

"Crystallographic Orientation of Biogenic Aragonite in Pearls"
Ren Lu
GIA Laboratory, New York

Explores the potential of laser Raman spectroscopy for material identification in pearls as well as determining the orientation of their biogenic mineral growth. Download article.

"Beryllium in Pink and Yellow Sapphires"
Andy Shen, Shane McClure, and Ken Scarratt
GIA Laboratory, Carlsbad and Bangkok

Describes a pink sapphire with natural beryllium and a yellow sapphire with an indeterminate beryllium source. Download article.

"Separation of Plagioclase Feldspars via Chemical Analysis"
Shane McClure and Christopher M. Breeding
GIA Laboratory, Carlsbad

Examines the geographic origin of feldspar based on chemistry and refutes allegations that Mexican material is being sent to China for treatment and sold as Chinese material. Samples from Mexico, Mongolia and the United States are analyzed. Download article.

"Jeremejevite: A Description of a 400 Crystal Collection from Namibia and a Preliminary Study"
Jitlapit Thanachakaphad
GIA Laboratory, Bangkok

A collection of rare jeremejevites, reportedly from Namibia, was recently brought to the GIA laboratory in Bangkok for research purposes. This article reports on initial testing of five samples and photos of the entire collection.

"Ruby and Pink Sapphire from Aappaluttoq, Greenland: Status of Ongoing Research"
Kamolwan Thirangoon
GIA Laboratory, Bangkok

This study presents spectroscopic, chemical, and inclusion analysis of 26 ruby and pink sapphire samples from Aappaluttoq, Greenland.

"Distinguishing Heated from Unheated Natural Spinels: A Short Review of Ongoing Research"
Sudarat Saeseaw, Wuyi Wang, and Kenneth Scarratt
GIA Laboratory, Bangkok and New York
John L. Emmett and Troy R. Douthit
Crystal Chemistry, Brush Prairie, Washington

While top-quality natural spinels have so far escaped large-scale treatment processes, some heat-treated goods are on the market. This report establishes the identifying criteria of heated spinels. Download article.

"Rubies Reportedly from the Niassa Region of Mozambique: A Preliminary Examination"
Vincent Pardieu and Jitlapit Thanachakaphad
GIA Laboratory, Bangkok

Attractive new rubies reportedly from northern Mozambique have begun to appear on the Thai gem market. The stones resemble rubies from Winza, Tanzania, but this study shows they can be distinguished by microscopic examination. Download article.