Opal
This enchanting stone derives its name from the Greek "opallios," meaning to see a change of color. Ranging from a flash of pastel color to the fiery intensity of the darker varieties, opals reflect light like dew drops in the sun. It should come as no surprise then, that opals have a very high water content, anywhere from 3-33%, but generally in the 6-10% range. The base color ranges from colorless to white, orange, blue, gray and black and in some instances yellow, red or purple. The actual play of colors occurs when a precious opal stone is moved, allowing for viewing in different directions, revealing a spectrum of colors from soft banded pastels to vibrant reds, greens, and blues.
Their unique color has made them long prized by royalty. An opal was featured in the crown of the Holy Roman Emperor, and is still among the crown jewels of France (including the 77-carat opal of Louis XVIII, kept in the National Museum of Natural History in Paris). The most treasured variety of opal is the black opal.
Opals are found in various parts of the world with Australia being the most notable source. They are also mined in Mexico, Honduras and the United States. It has a Mohs hardness of 5.5-6.5. |
Eng 
ä·Â
