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approx. size : 16.5 mm
approx. total weight : 23 grams = 115 carats
4 beads, center drilled
Listing is for the exact 4 beads as pictured.
Color of gemstone may vary slightly from screen to screen.
** Opal was formed many millions of years ago, when a combination of silica and water flowed into cracks and spaces in the ground. This then gradually hardened and solidified to become opal. It is an amorphous form of silica, a mineraloid form, not a mineral. 3% to 21% of the total weight is water, but the content is usually between 6% to 10%. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock.
Opal's internal structure makes it diffract light, depending on the conditions in which during its formation if the tiny silica spheres that make up the Opal have aligned so that the spheres are unformed and form a dimensional structure grid. If so, then, it can take on many colors that we say it has “play of color” that most people associate with precious opals.
When there is no alignment of uniform silica spheres it is still considered Opal (or Opalite) but there is no flash of color and therefore called common Opal.
Opal is the national gemstone of Australia, which produces 97% of the world's supply.