Opal is a hydrated amorphous form of silica. Instead of silicate crystals forming, like quartz or agate, the silica are suspended or it is 'mineraloid'. Precious Opal flaunts the spectrum of 'flash' within it's structure. Any color of the spectrum can show up in the refraction and the over-all color of the Opal can vary as such. Above is a 'Crystal Opal' and lower, a 'Boulder Opal'.
There are several different kinds of Opals and quality levels among them. Not all Opals have 'flash'; the luminescent, glow and refraction of colors. Precious Opal has flash and comes in many different varieties such as Black, White, Crystal, and Boulder. Boulder Opals are my personal favorite because they are left in the 'mother-stone' for better flash and strength, and they are typically 'free-form' polished.
Boulder Opal and Keum Boo
This Boulder Opal, from Australia, exhibits the colors of the Caribbean with a bit of the Matrix, like land, coming up through the sea. Coupled with Fine Silver and Gold Keum Boo, texture of metals meets the ocean of stone.
Unlike 'White Opal' that is translucent or opaque, crystal opal is transparent like jelly. It still exhibits flash and can be any color of the spectrum. These green Crystal Opals were close enough in match to pair for earrings with Keum Boo.
I accumulated my Opals over 25-30 years ago from the Australian miner. After hording them for that amount of time, a few are being liberated at a time. Most of these are Crystal or Boulder Opals of individual quality so individual, creative settings are being created for each. Check the 'New Jewelry' section for the latest pieces and use the Contact page for inquiries.
Not So Common Opal
Opal can happen anywhere there are silicates, water, and the perfect set of variables. Since silicates love to make their way into voids with water, the opals could be fossil shells, fissures in the cracks of rocks (most gem quality opal material), and even in Thundereggs. Common Opal is Opal without the flash. It appears commonly and shows up occasionally in gem form, mostly as pink material. This specimen is a Thunderegg and the reddish material around the Opal is Rhyolite. It took a beautiful polish.