Topaz is commonly yellow, orange, or brown in color. Pink topaz is a lesser-known color. “Imperial” topaz is a pink-orange color that is reminiscent of zinfandel wine. Colorless topaz is an historic diamond imitation. Topaz is found in many areas around the world, with South America and Sri Lanka leading production.
Rock Solid Facts
Mohs Hardness: 8
Cleavage/Fracture: one direction of perfect cleavage
The most common treatment is the irradiation of colorless or very light yellow topaz to cause blue color. Treatment of topaz with thin film coatings results in any color. Blues, yellows, browns, reds, greens, and iridescent examples of coated stones are available.
|This topaz was damaged when moderate pressure was applied to a small cleavage. |
photo courtesy of Anton Nash.
Topaz has one direction of perfect cleavage that makes it prone to breakage (especially if fractures are present). Topaz often has liquid inclusions. Cleaning in a steamer or ultrasonic can cause damage in stones with fractures or liquid inclusions.
If dealing with a hard to replace pink “Imperial” topaz, a customer’s stone, or a custom cut stone, the safest course of action is to clean the jewelry with a soft brush and warm soapy water. If the stone is a stock size and color that is easily replaceable, you may feel confident enough to steam and ultrasonic clean. Just be sure that you are very comfortable with the possibility of having to replace the stone.
At the Bench
The primary issue with topaz that must be remembered at the bench is its one perfect cleavage direction. Hammering or putting pressure on a topaz runs the risk of cleaving the stone into pieces. Routine stone tightening on a prong set topaz can result in cleaving the stone. Setting a topaz in prongs presents a greater risk than tightening. To minimize the risk, avoid alloys that are very hard, as well as overly thick prongs. Cut stone seats with care and smooth away any burrs left by tools.
The design of a piece of topaz jewelry should take into account the stone’s tendency to cleave. Use slightly thinner stone settings or more malleable alloys. Channel settings are difficult, as pushing the girdle edge of the stone into the channel is a perfect opportunity to cleave the stone. Designs should also be engineered in a way that protects the topaz from any sharp blows during normal wear.
Files and burs can cause scratches on the stone. The most common tool damage on a topaz takes the form of small chips along facet junctions, again due to the cleavage. This type of damage is obvious and should be avoided by using files with safety edges and doing as much sanding and filing as possible prior to stone setting.
Topaz cannot tolerate heat from a jeweler’s torch. Retipping with the stone in place is not possible unless using a laser welder. Sizings and other repairs can be done with the stone protected in a water bath or heat-shielding product. It is safest to remove the stone if possible.
Coated topaz must be handled with the utmost care, as the coating can be worn off or otherwise affected by buffing compounds.
Tools That Rule
- Laser welders allow topaz to be left in place during repairs. However, make sure a skilled operator uses the machine, as hitting the stone with the beam will likely result in damage.
- Heat shields or water baths are necessary in situations where topaz cannot be removed from the setting during repair.
- A safety edge file prevents chips and abrasions when finishing prongs.
Communicate with the Customer
Customers need to know that blue topaz is irradiated and heat-treated to its current color. They can be assured that the stones are not radioactive. In the case of a coated topaz, the customer absolutely has to understand that the color is not natural and may not be permanent if worn roughly.
Sharp blows, especially to rings and bracelets, often result in a broken topaz. Make sure the client understands that topaz is not an appropriate stone for the gym or the garden.
In repair take-in situations, make sure the customer understands that topaz can cleave in the process of repair. Before you accept the job, fully inform the customer about what you will and will not be responsible for if the stone is damaged.