Historically, topaz is one of the most important gemstones. Topaz’s high refractive index, hardness of 8, and capacity for taking a fabulous polish make it an excellent choice for any jewelry application. Its wide range of colors makes it easy to complement any outfit. Topaz is November’s birthstone. Blue topaz is the 4th wedding anniversary stone. Orange topaz marks the 23rd anniversary. Blue topaz is also the official gemstone of Texas. Orange topaz is the official gemstone of Utah.
Whatever the occasion, our topaz buying guide can help you learn to evaluate a topaz’s qualities.
Clarifying The Terms “Precious” and “Imperial” Topaz
Although the distinction between precious and semi-precious gemstones has fallen out of favor, the term “precious topaz” is still frequently encountered. Currently, it is used to refer to stones with a rich yellow to a medium, peachy orange color. The term originated as a way to distinguish topazes of these colors from citrine and smoky quartz gemstones. Although these are distinct gem species, these stones are sometimes misidentified, accidentally or deliberately, as topaz.
“Imperial” topaz usually refers to stones with a very saturated reddish orange color. This is how the International Gem Society (IGS) defines the term. However, the term is sometimes applied to intense yellow and orangish topaz as well as pink topaz. When dealing with imperial topaz, verify the actual colors of the stone.
Topaz Buying And The 4 Cs
Pink and red are the rarest and most highly valued topazes. Orange and yellow follow. Hue and saturation are the prime value factors in these varieties. In general, the more pink or red mixed in with the yellow or orange, the higher the value. There is a significant decrease in prices for topazes of other colors, particularly blue and colorless. Size comes at a premium for all topazes except blue and colorless.
The IGS topaz value listing has price guidelines for topazes with different color grades, sizes, and cut styles.
In the GIA color grading system, color consists of three qualities: hue, tone, and saturation. The basic hues are red, orange, yellow, green, blue, violet, and purple. Tone refers to a color’s relative lightness, from colorless (0) to black (10). Saturation refers to a color’s intensity, from grayish or brownish (1) to vivid (6). The dominant hue is capitalized. Other hues present are not capitalized and may be further described as “sl” for slightly and “st” for strongly.
The top color for an imperial topaz consists of a hue of orangish red (oR) or red (R), a medium tone (5), and a strong saturation (5). The color grade is noted as oR, R 5/5.
Blue topazes are some of the least expensive gemstones on the market, at prices up to $26 per carat. Top color for blue is very slightly greenish blue to greenish blue, with medium tone and strong saturation (vslgB, gB 5/5).
Brown or sherry-colored topaz is fairly common. It has lost popularity in recent decades but can be a beautiful gem. Guerrero, Mexico produces some of the finest brown topaz. It’s sometimes deep red in one direction.
Clarity refers to a gem’s transparency and anything that can impact how it transmits light. Yellow, blue, and colorless topaz are usually Type I gems, meaning they are usually eye clean and free of inclusions. (Included pieces of these colors should see a steep drop in price). Pink and red topaz are more likely to have inclusions, though these do not usually impact their price.
Brazil is the main producer of precious topaz. Most of this material is native cut. Custom re-cuts for these stones are strong value enhancers. Common cuts for topaz include emerald cuts, ovals, cushions, and pears.
For blue topaz, the cut often adds as much or more value to the piece than the material itself. The fact that the rough is available at moderate prices in rather large, clean pieces means that spectacular fancy and non-traditional cuts, as well as carvings, are available at reasonable prices.
There is an exponential jump in the value of precious topaz for stones larger than 5 carats and again for stones larger than 10 carats.
Topaz Buying: Jewelry Considerations
Topaz is a durable stone and has no special sensitivity to common gemstone cleaning chemicals. Protect this stone from hard knocks and keep it away from steamers and ultrasonic cleaners and it should last for a long time. At the cutting stage, topaz’s perfect cleavage can present a challenge, but cutters generally orient the table of the stone 5-10% off the cleavage plane, which results in a pretty stable stone for wearing in a ring, pendent, earring, or brooch.
Treatments and Enhancements
The subject of topaz enhancement is a complicated one. It is prudent to assume that some form of heat and/or irradiation has been used on stones prior to cutting (except colorless stones). The color of precious topaz is generally heat and light stable. Some natural and enhanced types of brown topaz, on the other hand, can fade dramatically in strong light.
Most blue topaz begins its life as colorless or very lightly tinted, natural crystals. They are then irradiated to change the color to blue and heated to stabilize the change. Neutron bombardment in a nuclear reactor produces the deep, slightly greenish or grayish “London Blue.” Electron bombardment in a linear accelerator results in the light, aqua-like blue known as “Sky Blue.” Combinations of both treatments produce the highly saturated “Swiss” and “Electric Blues.” If neutron bombardment has been used, there is residual radioactivity. The gems must be held, up to a year, before they have “cooled” enough to be worn!
In general, blue topaz is modestly priced. However, due to recent shortages, the “London Blue” color has outstripped the others in value. The shortage is due to poor economics. Reactor time is expensive, and there are more profitable gems that can be treated without the need for such a long holding period.
The modest value of most blue topaz creates little incentive for selling synthetics.
Mystic topaz is a popular enhancement. Through a diffusion or vapor deposition process, the surface of a gemstone is coated with colors such as teal, red, and sea green as well as multicolors. Such stones are attractive, but the treatment is not permanent. With their extremely thin coating, they must be handled very gently. Any scratch or abrasion can mar the surface layer.