Characterizing Natural-Color Type IIb Blue Diamonds

King, John T.; Moses, Thomas M.; Shigley, James E.; Welbourn, C. M.; Lawson, Simon C.; Cooper, Martin

doi:10.5741/gems.34.4.246

Cited by 45 publications

(41 citation statements)

References 26 publications

(32 reference statements)

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“…This device is no longer manufactured, but a sensitive ohm-meter can adequately determine if a diamond is electrically conductive (ohmmeters measure resistivity, which inversely correlates with conductivity). Boron impurities in the diamond lattice cause both natural and synthetic type IIb diamonds to be electrically conductive (Collins, 1982;King et al, 1998). No other diamond type shows this property.…”

Section: Inclusions and Strain Patterns: Gemologicalmentioning

confidence: 99%

See 1 more Smart Citation

The "Type" Classification System of Diamonds and Its Importance in Gemology

Breeding¹,

Shigley²

2009

Gems & Gemology

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112

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Section: Inclusions and Strain Patterns: Gemologicalmentioning

confidence: 99%

“…Many type IIa pink diamonds are thought to originate from Brazil, Africa, and India (King et al, 2002). Type IIb diamonds are less widely distributed; most come from India and the Cullinan (formerly Premier) mine in South Africa (King et al, 1998).…”

Section: Box A: Summary Of Color-producing Diamond Defects Not Relatementioning

confidence: 99%

The "Type" Classification System of Diamonds and Its Importance in Gemology

Breeding¹,

Shigley²

2009

Gems & Gemology

Self Cite

112

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“…All the CVD synthetic diamond samples grown from gas mixtures containing diborane showed colors equivalent to a range from Fancy Light grayish blue to Fancy Deep blue (again, see figure 5). All had optical absorption properties typical of type IIb diamond (see King et al, 1998). The color arose from boron-related absorption extending into the visible part of the spectrum, with decreasing absorption from the red to the blue.…”

mentioning

confidence: 99%

Identification of Synthetic Diamond Grown Using Chemical Vapor Deposition (CVD)

Martineau¹,

Lawson²,

Taylor³

et al. 2004

Gems & Gemology

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140

151

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Studies carried out at the DTC Research Centre have shown that single-crystal CVD synthetic diamond is clearly distinguishable from natural diamond. This article presents information about the CVD process, the history of its development, the different kinds of CVD synthetic diamond material that can be produced, and properties that differentiate them from natural diamond. The authors studied more than a thousand CVD synthetic diamond samples that were grown for research purposes using a range of different process conditions. Absorption, photoluminescence, and cathodoluminescence spectra of these CVD synthetic diamond samples showed a range of different impurity-related features not seen in natural diamond. Photoluminescence imaging is also useful in identifying CVD synthetic diamond, and X-ray topography may give supportive evidence. The effectiveness of the Diamond Trading Company Diamond Verification Instruments for identifying CVD synthetic diamond is also described.

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“…tone (the lightness to darkness of the color) and moderate to strong in saturation (the strength or purity of the color; King et al, 1998). The Hope's grayish blue color, compared to the blue of the Wittelsbach-Graff, led us to expect a very slightly less saturated and more "steely" appearance, which we did observe.…”

Section: Need To Knowmentioning

confidence: 46%