Figuring out uncooked opal is a vital step in assessing its high quality and worth. Opal is a hydrated silica mineral that reveals a singular play-of-color, or iridescence, when considered from completely different angles. This phenomenon is brought on by the diffraction of sunshine inside the opal’s inner construction. Uncooked opal is usually discovered within the type of nodules or lots, and it will possibly fluctuate in colour from white to black. Essentially the most precious opals are those who exhibit a vivid and intense play-of-color.
There are a couple of key traits that may allow you to to establish uncooked opal. First, opal is a comparatively tender mineral, with a hardness of 5.5 to six.5 on the Mohs scale. Because of this it may be simply scratched with a knife or different sharp object. Second, opal is a translucent to opaque mineral, that means that it permits some gentle to cross by means of it, however it’s not fully clear. Third, opal has a conchoidal fracture, that means that it breaks with a curved, shell-like floor.
