The Chanthaburi-Trat Gem Field, Thailand

Keller, Peter

doi:10.5741/gems.18.4.186

Cited by 28 publications

(16 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Heat treatment experiments were also undertaken by George Rossman on a number of pale blue stones. As would be expected from a titanium-poor sapphire the heat treatment resulted in the oxidation of ib iron to produce a golden color (Keller, 1982) rather than a deeper blue.…”

Section: Descriptionmentioning

confidence: 91%

See 1 more Smart Citation

Sapphire from the Mercaderes—Río Mayo Area, Cauca, Colombia

Keller¹,

Koivula²,

Jara³

1985

Gems & Gemology

Self Cite

View full text Add to dashboard Cite

Section: Descriptionmentioning

confidence: 91%

“…Many major sapphire deposits around the world originated in allzalic basalts, including the deposits in Cambodia (Jobbins et al, 1981), Thailand (Keller, 1982), and Australia (Thompson, 1982). In most of these deposits, accessory minerals include blacli spinel, ilmenite, zircon, olivine, pyrope garnet, and augite.…”

Section: Location and Occurrencementioning

confidence: 99%

Sapphire from the Mercaderes—Río Mayo Area, Cauca, Colombia

Keller¹,

Koivula²,

Jara³

1985

Gems & Gemology

Self Cite

View full text Add to dashboard Cite

“…Burmese rubies are pale pinkish to deep red and some pure crystal has more vivid pigeon colour (Keller, 1983). Thai rubies exhibit colour variation from strongly violet to deep crimson (Keller, 1982). The variation of impurities in ruby depends on the sources of origin which has been reflected in their colour from different places.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic and Microstructural Studies of Ruby Gemstones of Sinapalli, Odisha

Sinha

Mishra

2015

Journal of the Geological Society of India

View full text Add to dashboard Cite

Spectroscopic and microstructural studies of ruby variety corundum samples of Sinapalli, Odisha have been carried out using various physical techniques. FTIR, Micro Raman, photoluminescence along with microstructural and energy dispersive x-ray spectroscopy (EDAX) data reveal presence of hydroxylated form of alumina on the surface with presence of Cr +3 chromophores. These gemstones contain zircon and rutile inclusions. Upon heat treatment, the colour of the ruby variety of gemstones improved by dissolving rutile inclusion inside the corundum lattice. Detailed data of the both untreated and heat treated samples are discussed in this paper.

show abstract

“…The benefits of this process with geuda sapphire led to successful experimentation with many types and colors of sapphire (e.g., Crowningshield and Nassau, 1981;Keller, 1982;Themelis, 1992;Emmett and Douthit, 1993) as well as off-color ruby. As a result, the vast majority of rubies and sapphires traded today have been heat treated.…”

Section: Introductionmentioning

confidence: 99%

Beryllium Diffusion of Ruby and Sapphire

Emmett¹,

Scarratt²,

McClure³

et al. 2003

Gems & Gemology

View full text Add to dashboard Cite

Over the past two years, the heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade. Although initially only orange to orangy pink ("padparadscha"-like) sapphires were seen, it is now known that a full range of corundum colors, including yellow and blue as well as ruby, have been produced or altered by this treatment. An extension of the current understanding of the causes of color in corundum is presented to help explain the color modifications induced by Be diffusion. Empirical support is provided by Bediffusion experiments conducted on corundum from various geographic sources. Examination of hundreds of rough and faceted Be-diffused sapphires revealed that standard gemological testing will identify many of these treated corundums, although in some instances costly chemical analysis by mass spectrometry is required. Potential new methods are being investigated to provide additional identification aids, as major laboratories develop special nomenclature for describing this treatment.

show abstract

The Chanthaburi-Trat Gem Field, Thailand

Cited by 28 publications

References 6 publications

Sapphire from the Mercaderes—Río Mayo Area, Cauca, Colombia

Sapphire from the Mercaderes—Río Mayo Area, Cauca, Colombia

Spectroscopic and Microstructural Studies of Ruby Gemstones of Sinapalli, Odisha

Beryllium Diffusion of Ruby and Sapphire

Contact Info

Product

Resources

About