A faceted Nano Gem from the Czech Republic designed to imitate Diaspore.

A relatively recent innovation, Nano Gems are created at temperatures of around 1500-1750° centigrade by fusing microscopic crystal aggregates in an amorphous matrix resulting in a transparent glass-ceramic with gem-like properties.

The Refractive Index varies between 1.61 and 1.64, and the materials dispersion is 0.015-0.02.
Hardness has been measured at 6.5-7.0 on Moh's scale.

The chemical composition depends on the required colour of the product, with Yttrium having been identified as one of the colouring agents, but is basically a mixture of oxides including silica, aluminium, zinc, lithium and magnesium.

The gem on offer here appears a burnt-orange-yellow colour in daylight and LED lighting, but reverts to a deep orange-red colour in incandescent illumination (images 2 and 6).

weight:  11.79 carats
shape:   Cushion shape cut
dimensions:   15.52 x 11.50 x 8.10 mm
treatment:  Not applicable