Nano-Polycrystalline Diamond

A completely transparent, polycrystalline synthetic consisting of randomly oriented, very tightly bonded nanoscale-sized diamond crystallites. (G&G Summer, 2012)

Using a sintering process, the material is created in a multi-anvil press at 15 gigapascals (2.18 million psi) and 2,300 to 2,500°C. High-purity graphite is thus converted directly into cubic diamond in a matter of minutes (G&G Summer, 2012)

Due to its polycrystalline nature, it is effectively uniformly hard in all directions at the macro scale and therefore requires special cutting and polishing methods - (G&G Summer, 2012)

Gems and Gemology journal (Fall 2012) pictured an 0.88 carat round brilliant stone cut from this material as an illustration accompanying the first-ever gemological characterization of NPD as a gemstone.
General Information
A variety or type of:Diamond
Physical Properties of Nano-Polycrystalline Diamond
Specific Gravity3.52
Skalwold E, et al, Characterization of a Synthetic Nano-Polycrystalline Diamond (2012) Gems and Gemology
Colour
Colour (General)Yellow
Skalwold E, et al, Characterization of a Synthetic Nano-Polycrystalline Diamond (2012) Gems and Gemology
TransparencyTransparent
Skalwold E, et al, Characterization of a Synthetic Nano-Polycrystalline Diamond (2012) Gems and Gemology May display a roiled appearance with magnification
LustreAdamantine
Skalwold E, et al, Characterization of a Synthetic Nano-Polycrystalline Diamond (2012) Gems and Gemology
Fluorescence & other light emissions
Fluorescence (Short Wave UV)Weak reddish orange
Skalwold E, et al, Characterization of a Synthetic Nano-Polycrystalline Diamond (2012) Gems and Gemology
Fluorescence (Long-Wave UV)Moderate chalky reddish orange
Skalwold E, et al, Characterization of a Synthetic Nano-Polycrystalline Diamond (2012) Gems and Gemology
Further Information
Mineral information:Nano-Polycrystalline Diamond information at mindat.org
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