I had a really fun photo assignment last month, photographing at the Royal Peacock Opal Mine in Nevada. This mine is a U-Dig operation where anybody can visit, buy a pass to dig in the mine, and hopefully uncover some amazing Opals.
These types of assignments are always fun, not only for what I get to photograph but also for the learning. The creation of Opals is absolutely fascinating, but rather than explain it myself, here is a quick explanation:
‘Opal is formed from a solution of silicon dioxide and water. As water runs down through the earth, it picks up silica from sandstone and carries this silica-rich solution into cracks and voids, caused by natural faults or decomposing fossils. As the water evaporates, it leaves behind a silica deposit. This cycle repeats over very long periods of time, and eventually, opal is formed.’ – Opals Down Under
What was explained to me, and I may not recall exactly, but this silica solution enters into the wood that is buried and estimated to be 12 – 15 million years old, and that wood eventually becomes petrified. Once the moisture leaves the solution, it becomes an Opal.