Black opal is the rarest and most prized form of opal, and it has what is called a black (or dark) body tone.
Black opalscome in all colors of the rainbow. Its dark body tone makes the colors of the opal face appear rich and intense. Color is the first thing you'll notice about an opal.
Red is the rarest and most sought after color. In order of value, the most valuable color is red, then orange, green, blue and purple. However, opal is never usually a single color. It is important to decide which is the dominant color followed by the secondary colors.
Use the dominant color as the color that will affect the price. If the body of the opal is transparent, also known as clear crystal opal, the stains of color can be seen below the surface. It is these specimens that have exceptionally high prices. Your customers may also be familiar with black or dark opal, which has a dark body color, which sometimes improves the brightness of the colors.
This is the rarest and most valuable variety of opal. It is generally accepted that the dominant background color is often the way the stone is identified. Black opals, such as those from Lightning Ridge, are generally considered to be the most valuable because the other colors of the vibrant spectrum and their patterns are best displayed against the black background. The term crystal opal refers to the “diaphanity” (transparency) of an opal, not its crystal structure, and is defined as any type of opal that is translucent to transparent.
The type of opal, body tone, brightness, pattern, thickness of the color bar, color play and faults play an important role in determining the value. Usually, opals with a black or dark body tone are more valuable than those with a white, light or crystalline body tone, because a stone with a darker body tone tends to display colors more vibrantly. Hays and his partner say they are selling the collection now because the market for colored gems in general and opals in particular is strong. In addition, electric blue opals are more valuable, as the hidden color bar makes the opal brighter than normal blue.
The background color, also called body color, is caused by the suspension of small impurities within the silica spheres of opal. The basic facts are that, due to the extreme transparency of this opal, it becomes a lower quality type of crystal opal that shows a faint and low-quality play of colors. If an N9 opal (which would be a white opal) has a magnificent color and brightness, it will exceed 10 times the value of N1. Valuable opal is the one with a black background color; the play of colors contains shades that span the entire spectrum; the sparkles are large enough and are evenly distributed throughout the gemstone; no inclusions or fractures. Opal is a diminishing resource and there is anecdotal evidence suggesting an increase of up to 25% per year in boulder opal prices and 15% annual increases in white, crystal and black opal.
Oval cut opals are generally considered more valuable than free-form, except with rock opals, where free-form is considered desirable. The backrest is often composed of obsidian, tinted black chalcedony, black glass, natural common opal or plastic. Fundamentally, opals from this region have a lower water content, which means that they are less susceptible to desiccation and less likely to exhibit “cracks” - fine fractures that affect the durability of the stone. The thickness of the color bar in opals is relative to the overall size and shape of the individual stone.
Opal classified as crystal, semi-crystal, white or gray that does not fall into a more specific category. The obvious problem with the term opal crystal is, of course, the basic fact that opal has no crystal structure. .