ORIGIN
Central Queensland, Australia

DIMENSIONS
5.3mm diameter x 3.5mm deep

CARAT WEIGHT
0.76ct

CUT
Round brilliant cut

COLOUR
Yellow Blue

TREATMENT
No heat

CUTTER
Cut locally

COMMENTS Parti sapphires are dramatic gemstones that feature two or more colour zones – blue, yellow and sometimes green. Each one has a unique pattern of colour zoning.

Typically, a gem cutter will orient colour zones to create a uniform body colour when viewed face-up. However, in parti stones, the cutter orients the zones in the crystal to maximise contrast. As a result, the stone shows distinct colour zones from certain angles that appear to change or blend into more shades when rotated.

Because the zoning in each crystal is unique, these highly desirable gemstones are usually cut into non-calibrated shapes and sizes that suit the zoning position, rather than for weight retention. Consequently, they are not seen in commercial mass-produced jewellery.

This unique blue/yellow parti-sapphire is very bright, well cut and eye-clean. It has not been treated in any way. It shows blue and yellow colour zones that blend and reflect forming shades of green. The cutter has selected a round brilliant cut which traditionally maximises light return and brightness; the reason why it is used so extensively for diamonds. It could have been cut into a less impressive fancy cut in order to maximise weight retention, however, I am personally glad this was not the case as the result is a very bright stone with loads of colour and personality.

This gem would be lovely as the hero stone in a special ring or a pendant, with or without accent stones, for example in a halo design.

Commercial quantities of sapphire have been mined for more than 100 years in numerous locations situated along the Great Dividing Range in Eastern Australia, from Tasmania to North Queensland. Major commercial deposits occur in the New England District in northern NSW – Inverell and Glen Innes – and the Central Queensland Gemfields – Anakie, Sapphire, Rubyvale and The Willows, as well as Lava Plains in North Queensland. Besides professional operations, there are many part-time artisanal hand miners and hobby fossickers on the Gemfields.

DURABILITY Sapphire’s high hardness – 9 on Mohs scale – and its excellent durability render it ideal for most types of jewellery settings.