Born in October? Discover Opal.....

Posted on the 3rd October 2017

Born in October? Discover Opal.....

Opal: October birthstone

Opal is probably the most famous phenomenal stone displaying an unparalleled play-of-colour; a rainbow-coloured kaleidoscopic effect. It really is quite mesmerising. Some types of opals lack the play-of-colour phenomenon and they are known as “common” or “potch” opal.

The main categories of opal are “black”, “white”, “crystal” (translucent body), “water” (gelatinous appearance), “boulder” (has a layer of solid brown ironstone on the back), “fire”(bright yellow to orange) and “assembled” (a black backing is added (doublet) and sometimes a transparent cap (triplet) ) but the most valuable are “harlequin” opals: they are black opals with a dark black, grey, blue, green or brown background that makes the play-of-colour flashes stand out most strikingly.

Tiny silica spheres in opals refract the light in the different ways displaying the typical kaleidoscope of colour you see. These gemstones are formed of hydrated silica, most commonly found in Australia and now Ethiopia. You can even get opalised fossils which are really quite beautiful.

Opals can be treated to improve their colour and they can undergo a sugar or smoke treatment that darkens their body colour which makes the play-of-colour more striking.

Depending on the transparency of the stone, which can be anything between semi-transparent to opaque, opals are mostly cut into cabochons but you also see them as faceted stones, beads and occasionally carvings.

Opal’s lustre is vitreous to resinous; it rates 5-6.5 on the Mohs scale and depending on the origin of the stone it might be very fragile which makes it more suitable for jewellery such as necklaces, brooches and earrings that are less likely to be knocked. If exposed to extreme heat or light it can crack or “craze” which is undesirable as it means the stone is unstable.

Visit our Inspiration page to see some examples of striking bespoke designs that our in-house designers have created.

Feeling inspired? Come to our showroom to buy, peruse or to find out more or book an appointment with one of our talented designers to Create Your Own very special item of jewellery.

Want to know more about gemstones? Check out our A-Z guide.