Opals have always been a favorite at Creative Goldsmiths. Its play and variety of color make it unique in the mineral world. However, there are many misconceptions about opal, that we hope to dispel.
Pricing and Choosing an OpalIt is important to note that all color and all stones are not created equal. Here is a list of color according to value first to last.
- Purple/Red – equally the most valuable
- Orange – great value
- Yellow – excellent – it is important to mix with orange & red
- Green – most common – however can be very valuable when vivid and when mixed with blue (peacock).
Ideally stones should face up with continuous sheets of color. These sheets are commonly called the palate.
When comparing one opal to another, compare palates and look for weak spots.
More weak spots = less value.
Some Opal Facts
Opal is a relatively hard stone, 5 to 6.5 on the Mohs’ hardness scale. (diamond=10, turqoise=5 to 6, emerald=7.5 to 8) There are 2 important factors regarding the cracking or crazing of opal. Opals are fairly hard, but they are not tough. Toughness, in plain terms, is a resistance to chipping. Therefore, in our opinion, opal edges should always be protected by the setting. We almost always bezel or inlay opal therefore putting an edge of gold or platinum around the stone.
The most important fact to remember when caring for an opal is that opal is silica, therefore it contains a large amount of moisture. If you own an opal PLEASE pay attention. You must hydrate your opal every 30 to 120 days depending on wear. Re-hydration is simple. Put your opal jewelry in a closed box with cotton and 4 or 5 drops of water. Do this for 4 to 6 hours and the opal will absorb the moisture through osmosis. This is a great way to prevent chipping and crazing. Crazing appears like small dried out crevice on your stone. This is easy to avoid with proper care, however crazing cannot be reversed.
TYPES OF OPAL
There are too many to list, therefore we will give you a brief description of the most popular varieties:
White opal is one of the most common opal varieties. It has a mostly white background with pin point arrays of color. White opal can be found in Europe, Australia, and the U.S. (Price range $20.00 to $400.00 per carat.)
Fire opal usually has a blue or blue/green background. It is mostly crystal silica. (Compressed and hardened sand.) Fire opal can range from common to utterly spectacular. The color of fire opal is hard to ignore: hot yellows, oranges, and reds so bright they look as though they might glow in the dark. Fire opal sometimes does have play of color but it does not need this. In the better varieties you find large flashes of color (known as palate or harlequin), or milky way type pinpoint color flashes. Fire opal is mined in Mexico, the result of ancient volcanoes! Fire opal can also be found in Oregon and British Columbia in Canada. Fire opal is also found in South America, Central America, Southwestern U.S., Europe, Australia, and New Zealand. (Price range $50.00 to $1500.00 per carat.)
Boulder opal could be called “wasteland wonder.” It occurs mostly in the desert outback of Australia and the western U.S. Boulder opal only occurs in arid conditions. It is formed when liquid sand or silica fills in fractures in rocks that were formed by seasonal rains. During long dry spells the silica hardens by evaporation. Because silica is composed of tiny particles stacked up on top and beside each other, they defract light in prismatic color patterns. The closer the arrangement of these particles, the better the play of color. In the case of boulder opals, these color flashes generally stand out better because they are against a very dark background. (Price range $150.00 to $3000.00 per carat).
Since 1901 Lightning Ridge has been the premier source for opal. Lightning Ridge is 500 miles NW of Sydney Australia and provides the worlds finest and most expensive opals. As a general rule, they have large ruby red, royal blue, verdant green, and sometimes purple flashes. (Price range $500.00 to $12,000.00 per carat.)
Black Crystal Opal
The word opal is the shortened version of the Roman word “opalus” or “play of color”. For centuries man has marveled at iridescence (color play) without understanding how it occurs. The invention of the electron microscope showed that the richness of opal color was the result of light diffraction or spectral effect. Light enters the stone and passes through a lattice of silica spheres into the center of the stone. No other opal does this as effectively as crystal black opal. Gemologists have found that the order, size, and arrangement of the spheres yield color. Black crystal opal is black opal with no “potch” or “matrix,” yet it has intense black/navy, blue/black, or blue/green to its color. (Price range $200.00 to $6000.00 per carat.)
There are two kinds of transparent opal. The first and most common is jelly opal. It has one color (usually orange or yellow) and may appear to have tiny bits of color suspended within the stone. The second is crystal jelly opal. It is very rare and can occur in all colors. In their best and most rare form, crystal jelly opals appear as crystal balls that feature a small but strong color play. (Price range $35.00 to $800.00 per carat.).
FROM OUR BLOG
DID YOU KNOW!
Our designer Mr. Irwin Gross has participated in the creation of such prestigious pieces as the Kennedy Center Medallion, the Eisenhower Liberation Medal and various pieces for the Smithsonian Institute.
Mr. Gross has won multiple awards for his intuitive ability to select the highest quality gemstones, which includes a national award in 1983 called the Diamonds Today Award.
DID YOU KNOW!