Gemology Hub / Gems Hub / Minerals Hub: June 2020

Tuesday, June 30, 2020

Treatments of Ruby and Sapphire by John Koivula

Thursday, June 18, 2020

Inclusions in Natural opal

Opal is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3 to 21% by weight but is usually between 6 and 10%. Because of its amorphous character, it is classed as a mineraloid, unlike crystalline forms of silica, which are classed as minerals.

inclusions in wood opal

Iron sulfide in opal

fern like a holographic play of colour patterns in opal

pyrite inclusions in opal

Iron oxide in opal

opal from USA

Clay mineral along with pyrite in opal

Play of colour in opal

Manganese oxide flower in opal

Iron oxide in opal

Chalcedony along with amphibole needles in opal

Green opal

Manganese oxide in opal

fluorite inclusions in opal

opal from Ethiopia

wood in opal

Agate like banding pattern in opal

Leopard opal

Conk opal

The same slides are in the form of video uploaded on youtube.

Thursday, June 11, 2020

Identification of Surface Diffused Synthetic blue Sapphire

Since 2015 a large quantity of a new blue diffused synthetic sapphire has appeared in the world market. In immersion of blue diffused sapphires showed the “spiders’ web effect” – a cut-related colouration pattern – and rather high titanium content on the surface of the samples. The synthetic blue sapphire usually displayed strong chalky blue fluorescence to SWUV lamp and mostly have cure bands and residue or gas bubble under the microscope.

residue & gas bubbles in synthetic diffused sapphire

colour concentration on the facets edges easily seen

When viewing the stones in methylene iodide solution with diffused-transmitted white light, blue diffused synthetic stones clearly display a “spiders’ web effect”