The definition of "Common opal" is a stone that does not exhibit a "play of color". Although most of these stones are also "common" in appearance and do not attract commercial attention, some of them are beautiful. This material is given the name "common opal" because it is found in many locations throughout the world. Some people in the trade also call common opal by the name "potch".
Beautiful Common Opal
Gemstone hunters seek out specimens of common opal that are attractive, colorful and and accept a lustrous polish. They can be beautiful but simply lack a play of color that would earn them the name "precious". Common opal is frequently cut as a gemstone and can sell for attractive prices.
Examples of Common Opal
Shown at right is a beautiful blue teardrop-shaped stone cut from common opal mined in Peru. It is 13x8 millimeters in size and weighs 2.3 carats. Also at right is a collection of common opal 4 millimeter beads ranging from white to pink to lavendar in color. The material used to produce these beads was also mined in Peru. The third photo at right shows two Morado Opal cabochons. "Morado" is Spanish for "purple" and some stones cut from purple material mined in Mexico are given the trade name "Morado".
Find it on Geology.com
More from Geology.com
Ant Hill Garnets - tiny garnets that ants haul to the surface and discard on their anthill.
Wrong Volcano! The most powerful eruption of the 20th century was misidentified?