Gemstones we love: opals, tourmalines and more (part 1)

Let’s begin with Opals; gem-quality opals are considered to be one of the most spectacular of all gemstones.  A single stone can flash every colour of the spectrum with an intensity and quality of colour that can surpass the “fire” of diamonds. The best opals can command prices per carat that rival expensive diamonds, rubies, sapphires, and emeralds.

When Australia’s mines began to produce opals commercially in the 1890s, it quickly became the world’s primary source for this October birthstone. Most opal is “common opal” or opal that lacks the colourful flashes known as “play-of-color”.

The rare specimens that exhibit a “play-of-color” are known as “precious opal”. Opalescence and “Play of color” are not the same. Opalescence is a “pearly luster of common opal” which not even common opal has, even when polished.

“Play-of-color” happens when million of microscopic silica spheres arranged in an orderly network diffracts the light. The size of the spheres and their geometric packing determine the colour and quality of the diffracted light.

In earlier times opals were prized throughout various cultures and thought to bring good fortune, good health, and foresight. Because opal has the colours of other gems, the Romans also thought it was the most precious and powerful of all. The Ancient Greeks believed that opals brought prophecy. The word opal derived its name from “opalus”, which means “to see a change in color”. The Bedouins believed that opals contained lightning and fell from the sky during thunderstorms.

Due to it being considered a 5 to 6.5 in MoH Hardness scale, when used in a ring, the best designs have a bezel that fully protects the stone. If you decide to wear an opal ring it is best removed during activities when impact or abrasion might occur.

FACTS:
Mineral: Hydrated Silica
Colors: Red, Blue, Green, Purple
MoH’s Hardness 5 to 6.5
No TWO opals are the same

QUALITY FACTORS
Color: Play of colour, intensity, and pattern are important value factors.
Clarity: Experts expect different levels of clarity for different types of opals.
CUT: Fine opals are often cut into irregular shapes that keep as much play of colour as possible.
Carat Weight: because of its low density, even large opals might feel very light and therefore are comfortable to wear.

SOURCES OF OPAL:
Australia – 1900
Mexico – 1900 best known for its FIRE OPAL, yellow, orange and red colours.
Ethiopia – 1990’s
Hungary, Indonesia, Brazil, Peru, Honduras, Guatemala, Nicaragua, Slovakia, Czech Republic and the USA.
BASIC TYPES OF OPAL
Precious Opal
Common Opal
Fire Opal
Precious Fire Opal – from Ethiopia, orange body colour but also contains an electric green to purple play of colour.

Whatever type of opal you prefer and whether it is your birthstone or not, you can wear it without superstition and recognize the opal is a lot like women, powerful, changeable, colorful, full of vibrancy and different hues and a stone that grown even more influential with time. To learn more about this most precious of gemstones, visit the GIA encyclopedia on opals.