Opal
Opal Facts
Opals have been worn since the age of Pharaohs. While modern science has developed a way to make synthetic stones that closely resemble natural Opals, the most valued and precious Opals are mined by hand. The best Opals come from Australia. In fact, 90% of all Opals come from Australia. The Opal is a silica gel layered and compacted beneath the earth's surface for many eons, resulting in prismatic layers of amorphous silica spheres that diffract light into an ever-changing rainbow of color.
Colors!
The distinguishing aspect of an Opal is the fire of color it exhibits. Opals that present dull or non-prismatic color are much less valuable than Opals that spring to life when touched by light. Precious Opals have bright color rendition evenly distributed throughout the stone. Color is said to "play" on the face of an Opal: changing when viewed from varying angles. Fire color is rated in terms of rarity:
- 1. Red (most rare)
2. Violet
3. Orange
4. Yellow
5. Green
6. Blue (least rare)
Grades
Many variables go into selecting a fine Opal. Generally speaking, Opals are graded on body tone (black being most desirable, semi-transparent least desirable) on a scale of 9 down to 1. Fire brilliance, hue and play are major factors in grading an Opal. Type, thickness of base color, and lack of imperfections are important factors as well.
Try It On
An Opal's fire can truly only be appreciated in person. Additionally, different types of Opal will lend themselves to certain jewelry settings better than others. Before purchasing your Opal visit a few jewelry stores and try them on. Many excellent retailers offer Opals via the web. Get educated about Opals and understand the retailer's warranty or return policy before you buy.
A Few Words About Opal Types
There are many types of Opals. Opals are mined in many places around the world (like Mexico and the USA), but none are as prized as Australian Opals.
- Precious Opal—a general term for fine Opals meaning that the amorphous silica spheres are evenly and thoroughly placed throughout the stone in orderly layers, creating a twinkling, brilliant universe of color captured in the stone.
- White Opal—white, gray or light base Opals the surface of which refracts a mainly pastel fire. A White Opal that is translucent (lacking a base color) is very precious and is called Crystal Opal. In Crystal Opals many layers of brilliant color are refracted from the interior and the surface of the stone.
- Black Opal—these very much sought after Opals actually come in a range of base colors from gray to black (a Black Opal may also be a Crystal Opal). Black Opals are the most rare Opal type and display a variety of colors from red to blue with great clarity.
- Boulder Opal—referred to as a "natural doublet," Boulder Opal is precious Opal formed on or in boulders. A piece of Boulder Opal jewelry will exhibit a natural dark back giving it the appearance of being black or very dark. The surface layer of Boulder Opal comes in all fire variations and is generally thin.
- Matrix Opal—this porous Opal is generally dyed or treated to resemble a Black Opal. It provides the same range of color brilliance and variation and can be very affordable. Be aware that unscrupulous dealers will try to pass Matrix Opal off as real Black Opal.
- Doublets & Triplets—thin layers of Precious Opal glued to a base (Doublet) or a base and a crystal top (Triplet). This is an attempt to give the Opal a black-like base color. When set, these Opals cannot be distinguished from their "whole" counterparts and are a good alternative when price is a consideration.
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