Begin the detective journey by compiling a list of possible gemstone identities based on colour and transparency.
The first and most obvious suspect is pink diamond. The exact cause of colour is still a mystery but may be related to plastic deformation of the crystalline structure. Most polished pink diamonds are well under a carat but are rare, beautiful and valuable.
Australia’s Argyle Diamond Mine, which supplies more than 90 per cent of the world’s pink diamonds, classify pink diamond according to colour – purplish pink, pink, pink rose or pink champagne – and intensity.
Consumers should be aware of any treatments, synthetics and imitations. Common imitations include synthetic cubic zirconia, glass, synthetic moissanite, yttrium aluminium garnet (YAG) and synthetic spinel.
Natural non-pink diamonds may also be irradiated and annealed to transform them to colour pink; synthetic or laboratory-grown pinks are produced using Carbon Vapour Deposition (CVD) or High Pressure High Temperature technology.
Look out for simple yet effective treatments, such as the application of a pink coating to white diamond pavilion facets.
Coatings may range from a high-tech vacuum-sputtered film to a crude dab of pink nail varnish. While sophisticated treatments and synthetics are identified using advanced spectroscopic analysis, simpler treatments like coatings can be detected using standard magnification.
Next on the pink checklist are two large, luxurious gemstones renowned for their pastel tones. Pale pink to lilac kunzite from the spodumene family, and salmon pink to orange-pink morganite from the beryl family are attractive and usually eye-clean. Both may be subjected to irradiation to create or intensify the colour.
Spinel may occur in a light-toned pink similar to kunzite; however, the latter is separated by its strong pleochroism.
Ever-popular sapphire and tourmaline are available in an enormous range of depths and intensities – synthetic sapphire is common and easily distinguished from its natural counterpart using standard equipment.
Next up is precious topaz, a rare and valuable collector’s gem. More commonly encountered is ‘pinked’ or heat-treated topaz. In its finest quality, pink topaz displays a purplish or red overtone and is called ‘imperial’. Be mindful that non-precious topaz may be coated to imitate precious varieties.
For pink gemstones of a more affordable nature, there is rose quartz, zircon and rhodolite garnet. Rose quartz is distinguished by low dispersion and soft translucence while pink zircon is highly dispersive with a diamond-like lustre. Zircon displays strong doubling of the back facets, a property garnet never displays.
Watch out for ‘composites’. Garnet-topped doublets are composed of a hard garnet top fused to a pink glass pavilion.
Some less common pink gems include apatite, scapolite, danburite, zoisite, diaspore and fluorite.
These pink gemstones are just the beginning of your gemmological journey; there are many more to consider. Consult your local qualified gemmologist or registered valuer for their expertise.
-