It’s October, and my birthday is in October. I like to think it should be more than just a birth-day; I like the idea of a birth-month. What’s better than a whole month of cake? Well, nothing really, but a month full of Opals, the birthstone for October, comes a close second.
Opals have so much interesting background, it’s hard to know where to start. Typically, when someone says opal, you think of this:
But did you know that this is also an opal?
So what actually determines that something is an opal? Opal is the product of seasonal rains that drenched dry ground in regions such as Australia’s semi-desert “outback.” The showers soaked deep into ancient underground rock, carrying dissolved silica (a compound of silicon and oxygen) downward.
During dry periods, much of the water evaporated, leaving solid deposits of silica in the cracks and between the layers of underground sedimentary rock. The silica deposits formed opal. ( Thanks to GIA for their definition)
So the silica deposits stack up in the rock, and when the light goes through it, you see the rainbow of colors that we all know and love. The color you see is dependent on the size of the silica spheres, from violet to red, and everything in between. The colorful ones are called Precious opals.
You might think diamonds would be considered the most precious. But according to lore, the Romans felt the opal was more precious than any other stone because it displayed all the colors of the rainbow.
Common opal, also known as “Potch” is still an opal, since it has the silica deposits, but the silica spheres are stacked randomly, so no opalescence is seen. Even still, the different common opals are lovely in their own way, and are what I love to wrap to show off each stone’s unique personality.
Next month, I’ll be featuring another fabulous stone from Australia that you probably haven’t heard of. If you like purple and black and/or olive green, be sure to read next month’s blog. Stay tuned.