EDUCATION 4 MINING STUDENT

Sunday, June 7, 2009

OPAL



What is it and where is it formed? Opal is a gemstone and the birthstone for October. Opals can form anywhere but are mostly found in places where there hot springs. It is sedimentary and is fluorescent a lot of times. It is a very easy stone to break.

How and where is it mined? Opals are mined using open pit surface mining. Sometimes opal mining areas are rented for the day. People can come in, mine the open pits, and take what they find. Opals are found in: Mexico, Australia, England, Czech Republic, and Western United States.

What is it used for? Opals are used in jewelry even though the stones crack easily. They are also used for collections of gemstones.

Opal

Opals are cut with rounded curves so that the colors will shine through. This is called opalescence.

Mineral Characteristic What the
mineralogists say
Kid's Guide: What it REALLY means!
Chemical Symbol SiO2∙n(H2O)

It has oxygen, silicon, and hydrogen in it.

Color White, colorless, light yellow or red, or gray Opal color depends on how pure the stone is. Most stones look white but have an iridescent shining of other colors, too. If they show colors, they are called precious opals.
Streak White If you crushed this stone, it would make white dust every time.
Transparency Transparent to translucent You can see through some of them clearly. Others would be blurry to look through.
Luster Vitreous - pearly The stone would look glassy or sometimes shimmery like a pearl.
Cleavage None It doesn’t break evenly in a pattern each time it is broken.
Fracture Conchoidal If it is shattered, the pieces have smooth surfaces.
Magnetism None It is not attracted to and will not attract a magnet.
Hardness 6 It is hard enough that it might scratch glass a little. It is upper middle on the Mohs scale of hardness.
Specific gravity 2 If you held an opal, it would seem light for its size.
Crystal Shape None It is not a crystal mineral.

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