About Peruvian Opal
Given the complexity that can come with sourcing genuine gemstones, we thought it wise to share some of what we have learned in assessing the quality of the gemstones purchased for our catalog. Whether you are new to purchasing opals or want to brush up on your opal knowledge, we’re sure you’ll find the information below helpful as you consider your purchase – happy reading!
Peruvian Blue and Pink Opal
While we stock many precious and semi-precious stones from around the world, Peruvian Opal is our flagship product. There are 3 grades of Peruvian Opal: First quality, second-third quality and mine run. It is mined in Ica, Peru. The first quality is an even color, good top color for cabochons. The second -third quality has more unevenness of color and more matrix in it. There may also be color striation as real opal will have color striation or unevenness of color due to the coloring. In the case of pink opal it is colored by a clay that surrounds it or it is usually found in, a mineral called palygorskite. Peruvian Pink Opal has a hardness of 6 versus Peruvian Blue Opal which is 5.5 hardness; making the pink opal some of the hardest opal in the world. Some pink opal also comes from Mexico and some other places in the world. Some of the very top material is saturated with color actually making it reddish. These are rare pieces, There also has been a little drusyA coating of fine crystals on a rock fracture surface, vein or within a geode found in the pink opal but mainly for collectors and in small areas.
The Pink Opal is high in silica in which this opal is almost a pink chalcedony
but it is opal and has opal cleavage. There is never a water problem with pink
opal and it is stabile.
In some cases, there may be a limited amount of dying done. However, this is
typically done overseas, usually in India or China. Top color pink opal is
expensive rough material. Mine run pink opal is whitish-brownish-greyish with
slight pink coloring and washed out color and is usually made into beads and
sold in tonnages overseas and can sometimes be dyed. Unfortunately, as top
color disappears on world markets, we believe that this stone will eventually go
the way of blue opal with mine runs being totally dyed and many imitations of
Fire opal is a crystal opal that actually has different colors inside the stone or a color play of fire inside a yellow, white, green, or red crystal base. Much of fire opal today has no "fire" in the stone and is a colored crystal opal. In past times, this was actually lower grade material. However, in today’s markets, this material is widely sought after.
Mexican fire opals are usually graded
by the miners in Mexico and tend to be priced very high. It is therefore important
to note that a lot of Mexican fire opal and other opals (including blue opal)
can have water problems. This means the opal is not dried sufficiently and
looses water from inside the opal. As a result, it can crack or craze as it dries
and loses water. Water loss can also make opal turn opaque eventually and
become ugly brownish in color to whitish as it loses water. These are hydration
problems and there can be some cures for them in rough and finished stones. The
same water or hydration problems can also be found in some chalcedony, agates, gem
silica and chrysocolla.
In Peru, there is a golden, also called honey or butterscotch opal. While this transparent to translucent variety is very beautiful, miners do not mine it anymore because much of it had water or hydration problems similar to those of fire opal from Mexico discussed above. In addition, there are orange agates or yellow agates and chalcedony which can be cut and misrepresented for fire opals. This can be determined by weight, as agate and chalcedony are much heavier then opal. Aside from hydration problems, some opals can be dyed. For example, some clear transparent opal can be dyed various colors or diffused. Acetone can usually test for dye in a stone.
African fire opals and Ethiopian
fire opal are far cheaper in price and usually come in larger pieces. However,
a lot of true fire opal is rare now.