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 totally different angles. This phenomenon is brought on by the diffraction of sunshine throughout the opal’s inside construction. Uncooked opal is usually discovered within the type of nodules or lots, and it may possibly differ in shade from white to black. Essentially the most worthwhile opals are those who exhibit a vivid and intense play-of-color.
There are a couple of key traits that may assist you to to determine 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, which means that it permits some gentle to go by means of it, however it isn’t fully clear. Third, opal has a conchoidal fracture, which means that it breaks with a curved, shell-like floor.
