Opal, being amorphous, is not really a mineral but a mineraloid. One of the scientifically accepted standards defining a mineral is that a mineral must have a crystal structure, which opal lacks. Many scientific groups and references, including the acclaimed Dana's System of Mineralogy, categorize Opal together with the "true" minerals. For this reason, Opal -- as well as other amorphous types that fall under the definition of a mineraloid.
It depends. All gemstones other than pearls and opals are crystals, but most crystals are not gemstones.
No. When opals were first found in Australia, they were not thought to be opals because they were a milky white in appearance. Opals found elsewhere in the world were mostly black.
Some opals are known as black opals, this is when they have a mainly black colour. In general a black opal is very dark blue and has flecks of other colours within
Opal is mined mainly in the country of Australia. It is also found in Nevada in the United States. You can also find opal at a Natural History Museum or a Rock Shop in your area, a good chance to study a variety in person. The Natural History Museum in Cleveland has an amazing collection. At a rock shop you can touch and feel the opal, so much better than browsing on the internet, which is a good source for information. One of the best rock shops is ROCK STAR CRYSTALS in Manhattan in NYC. They have a large variety of opals to look at, including fire opals, pink and blue andean opal, australian opals, ethiopian opals, honey opal, green opal, and even opal jewelry. Might be worth a visit to NYC just to check them out - and you can be awed by the mineral collection at the NYC Museum of Natural History at the same time!
Opals in Queensland are mined at Yowah, just outside of Quilpie in the far west of the state.
It depends. All gemstones other than pearls and opals are crystals, but most crystals are not gemstones.
No. When opals were first found in Australia, they were not thought to be opals because they were a milky white in appearance. Opals found elsewhere in the world were mostly black.
Opals are amorphous because they have no definitve shape. As an example, quartz has a specific crystal shape. Opals can be any shape.
Nobody MADE opals. They're mined out of the ground.
Opals cannot be used as foods. They are hard, precious stones.
Neither opals or any other gemstone will make you invisible.
Some opals are known as black opals, this is when they have a mainly black colour. In general a black opal is very dark blue and has flecks of other colours within
Three different types of Opal are found in Australia:Fire Opals are mined in South Australia near Coober Pedy.Black Opals are mined in New South Wales near Lightning Ridge.Boulder Opals are mined in the western Queensland.
No they do not shrink.
Mexico does not have an 'official' gemstone. It is however, the largest producer of silver in the world.
Yes. Coober Pedy is still a major producer of opals.
Opals in Queensland are mined at Yowah, just outside of Quilpie in the far west of the state.