Picture Guide to Opals
Black Opal
Opal which is found with a natural black or dark background. This background can range from pitch black to grey giving the stone are darkish appearance and when seen from the top is opaque [Not allowing light to pass through]. It is the dark background which allows the brilliant colors. Black opal can be any color. The specimen pictured has a dominant color of blue. It is approximately 1-1/2 cm in length.[This particular stone has now sold].
Dark Opal
Dark opal is found on most fields. It’s background color ranges from grey to near black.. Black opals are in the same family as Dark opals (also opaque- not allowing light to pass through). They are just dark opals with a blacker background. As the background of this stone becomes lighter and greyer it gets closer to light opal and its sometimes difficult to decide whether a dark opal should be categorized as dark or light. It’s often in the eye of the beholder.
Boulder Opal
A form of black or dark opal although it must be said that there are light colored boulder opals as well as dark and black. Boulder opals are still attached the mother rock they developed in
Boulder opal chips
Split faced boulder
As the title insinuates, this is a boulder opal that has been split along the vein of color, resulting in two identical pieces, one concave and one convex. This amazing natural appearance results in an identical pair that can be used as earrings if they are small enough or for specimen collectors.
Boulder opal Abstracts
(this is our terminology and is not an official description) but we feel that it best describes the endless varieties of these unusual opals often call ‘fun stones’, an expression that really doesn’t tell you anything about what they are.
Opal Carvings
As the term suggests, opal, both boulder ironstone and white or black opal is often used to carve figurines
Picture Stones
have received this name because from time to time as an opal is opened up from inside a boulder opal (particularly) or a black opal, something comes out that amazingly looks like a an item from nature, such as an animal, a rainbow, a bird, a fish, etc. the variety is endless.
White Opal
A solid opal with an opaque [non see-through] light background. White opal is often called milk opal because of its light appearance. Crystal opal is of the same family but it is more translucent and sometimes transparent whereas the color of white opal is on the surface. This type of opal can appear in all fields but Coober Pedy is famous for it.
Light Opal crystal This type of opal does not have a dark or black background and hence has a more delicate less dramatic appearance because the surface is not opaque and the light is able to shine right through the stone.
Dark Opal Crystal
This is when the crystal opal has a darker appearance within it’s body.
Andamooka Painted Lady
This stone is what could be called the South Australian ‘boulder opal’. Not because it is boulder ironstone but because it comes in large chunks like boulder and is often split out of the ground along the lines of color. It is pale in appearance but sometimes has some dark potch in the background of the color which gives it an attractive feature.
Mosaic Opal
The previously described opals are all naturally formed. Mosaic opal is created by a skilled artist who assembles the small pieces of natural opal into a mosaic pattern. These Slivers of genuine opal are assembled into an irregular tiled pattern with rivers of black potch framing each unique opal tile. Mosaic opals make stunning stones for all types of jewelry and allow the jeweler to include a wide range of colors within an affordable piece. This assembly of small opal pieces is not to be confused with the Harlequin opal which features squarish spangles of color appearing naturally in the opal face. It is the rarest and most expensive opal.
Matrix Opal This type of opal comes in two categories namely:
Boulder Matrix which is a completely natural stone made up of boulder ironstone with flecks of precious opal showing throughout the stone. These come in endless varieties from Winton to Yowah to Koroit.
Andamooka Matrix is a natural stone that, when it comes out of the ground is quite pale in appearance. By impregnating it with a black carbon process, the stone turns dark and when cut and polished, takes on the appearance of black opal. However, keep in mind that even though the stone is natural, there is a man made treatment involved which has to be stated at point of sale.
Composite Opals
Are natural opals that have been assembled with a dark or black backgrounded that is cemented in place so that the stone takes on the appearance of black opal. Opal is one of the only stones that can cater both for someone who can afford a large amount of money or someone who only has a few dollars. Composite opals such as doublets, triplets, and mosaics are still real opals and can be stated as such with the qualification that they have been assisted by man with the installation of a dark backing, or in the case of triplets, with a crystal protective cap as well.
