Opal is one of the world's most popular gemstones. Opals are the birthstone for the month of October and the 14th anniversary gemstone. Opals can flash every color of the spectrum with an intensity and quality of color that is stunning!
Opals can be found around the world with famous sources in Australia, Ethiopia, Mexico and Nevada. Opals form as precipitates from hot waters of geysers or hot springs – it can show up as veins in a rock, globules or crusts and even sometimes as stalactites and stalagmites. Opal can also slowly replace the exoskeletons of many marine organisms or wood creating beautiful shimmery fossils. There are many types of opal found in deposits around the world. Precious opal is what people usually think of when they think of opal but there are a variety of opals. For example, fire opals are known for their intense red, orange and yellow colors and are found frequently in Mexico. Boulder opal show up as veins in their host rock and common opal has color, pattern and beauty that can be anything but common.
Mineralogically, opal is a hydrous silicon dioxide (similar to quartz but with water in its composition due to how it forms). It used to be believed that opals were amorphous, without a crystalline structure, but it is now known that opal often forms as very small spheroids. The opalescence, or shimmer, that make opals so attractive comes from different amounts of water and different sizes of the spheroids in different layers that refract light differently.
Opal is softer and more easily chipped than most other popular gemstones. It has a hardness of about 5.5 to 6.5 on the Mohs Hardness scale (10 is hardest and 1 is softest). The best opal jewelry designs protect the stone – particularly if they are in pieces such as rings that are more subject to impacts and abrasion. Opal jewelry is beautiful but a bit fragile and it is best to remove your beauties during activities when physical damage might occur. Because of the water within the stone, it is also best to not wear opals in water that is hot or high mineralogical content such as hot tubs, hot springs or pools (edited by Martin Prinz, George Harlow, and Joseph Peters. Simon And Schuster's Guide to Rocks and Minerals. New York :Simon and Schuster, 1978.; https://geology.com/gemstones/opal/).
Opal is believed to have healing properties that intensify emotions , releases inhibitions, encourages independence and stimulates originality and creativity. Opal is believed to help release anger and in expressing one’s true self. Opal is also believed to strengthen memory and bring loyalty. It encourages spontaneity and an interest in the arts (https://www.charmsoflight.com/opal-healing-properties).