Like the months of June, November and December, October belongs to the elite club of months with 2 gemstones to celebrate its people. October’s birthstones are Tourmaline & Opal and today we will be sharing fun information about the precious stone Opal.
Opal’s name originated in ancient Rome where it was called “opalus” which was synonymous with “precious stone”. Opals are valued for their unique shifting colors in rainbow hues – a phenomenon gemologists call “play of color”.
Play-of-color occurs because opal is made up of sub-microscopic spheres stacked in a grid-like pattern, like layers of ping-pong balls in a box. This structure breaks up light into spectral colors and the colors you see depend on the sizes of the spheres. Those approximately 0.1 micron (one ten-millionth of a meter) in diameter produce violet. Spheres that are about 0.2 microns in size produce red while those in between produce intermediate hues.
Myths / Legends
The ancient Greeks believed opals gave their owners the gift of prophesy and guarded them from disease and throughout most of history opal has been regarded as the luckiest and most magical of all gems because it can show all colors. Once, it was thought to have the power to preserve the life and color of blonde hair!
Opals are more commonly mined in Australia, but are also found in Mexico, Brazil, Ethiopia and other countries Although experts divide gem opals into many different categories, the main types are:
- White opal – translucent to semi-translucent with play-of-color against a white or light gray body color.
- Black opal – translucent to opaque with play-of-color against a black or other dark body color. The market supply of this type is extremely limited, and so it is considered the most valuable.
- Fire Opal – transparent to translucent with brown, yellow, orange, or red body color. This material, which often does not show play-of-color, is also known as “Mexican opal,” “gold opal,” or “sun opal.”
Caring For Opal
Opals are a 6 on Mohs scale of hardness and are softer than other gemstones like emerald, jasper, etc. so should be worn and stored carefully to prevent scratching and protect them from hard blows. Opals are generally stable to light, but heat from intense light can cause fracturing (known as crazing). They should not be exposed to acids or caustic alkalis. Loss of moisture and crazing can result from storage in airtight containers, such as safe deposit boxes so should be stored in breathable bags like pearls.
To clean Opal, use warm soapy water (made with mild dish soap) and a soft bristled toothbrush. Do not use ultrasonic or steam cleaning.
Opals make great & beautiful stones for gifting. Consider one in jewelry pieces like cufflinks for dad or the special man in your life or for bridesmaids during an October wedding.