Ten Topaz Gemstone Facts (November Stones)
Ten Topaz Gemstone Facts
1. Topaz is an 8 on the Mohs Hardness Scale
Topaz has a Mohs hardness of 8, putting it considerably above quartz, which has a hardness of 7. This makes topaz resistant to everyday scratching and suitable for jewelry. However, hardness is not the same as toughness. Topaz has perfect cleavage, meaning it can split if struck in the right direction, so a hard knock can damage or even break a topaz gemstone.
This is an interesting example of why a gemstone's durability depends on more than just its hardness. Topaz may be difficult to scratch, but it still needs reasonable care when worn in a ring or other jewelry that receives frequent knocks.
2. Topaz comes in many more colors than blue
Blue may be the color most people associate with topaz, but it represents only part of the gemstone's color range. Natural topaz can occur in yellow, orange, brown, pink, red, purple, green and colorless varieties, with some colors being particularly rare.
The most highly prized colors include vivid red and the reddish orange colors generally described as Imperial topaz. Pink and purple topaz can also be exceptionally attractive and may resemble much more expensive colored gemstones.
3. Most blue topaz is treated
One of the biggest surprises about topaz is that the blue topaz commonly found in jewelry is usually not naturally blue. Much of it begins as colorless topaz and is treated using irradiation and, depending on the process, heat to produce different shades of blue.
The treatment created a huge market for affordable blue topaz, making blue one of the most familiar forms of the gemstone. Naturally occurring strongly blue topaz is much rarer than the large quantities of blue topaz available commercially.
4. Imperial topaz is particularly rare
Imperial topaz is one of the most desirable varieties of topaz. It is generally associated with attractive orange, reddish orange, pinkish orange and red colors, although there is no universally agreed official definition of exactly which colors qualify as "Imperial."
Fine red topaz is extremely rare. GIA reports that red represents less than one-half of 1 percent of facet-grade topaz material.
The finest Imperial topaz is particularly valued for its rich color and can be considerably more valuable than the plentiful blue varieties.
5. Topaz can show more than one color
Topaz is pleochroic, which means that a gemstone can display different colors when viewed from different directions. This effect is particularly noticeable in some yellow, orange and reddish varieties.
In a well-cut gemstone, pleochroism can contribute to the stone's appearance. In Imperial topaz, for example, reddish color may appear more strongly in particular directions, adding another dimension to the gemstone's color.
6. Topaz can grow into enormous crystals
Topaz is remarkable for the enormous size that its crystals can reach. The Smithsonian's National Museum of Natural History has two exceptional topaz crystals from Minas Gerais, Brazil, weighing 31.8 kilograms (70 pounds) and 50.4 kilograms (111 pounds).
GIA also records a transparent topaz crystal from Minas Gerais weighing an astonishing 596 pounds (271 kilograms).
This ability to grow into huge crystals is one reason topaz is fascinating to mineral collectors as well as jewelry enthusiasts.
7. One famous topaz weighs more than 22,000 carats
The Smithsonian's National Museum of Natural History is home to the American Golden Topaz, a spectacular golden-yellow topaz weighing 22,892.5 carats, or about 12.3 pounds. It was cut from a much larger Brazilian rough crystal that originally weighed about 26 pounds. (si.edu)
The finished gemstone has 172 facets and measures approximately 17.5 by 14.9 by 9.3 centimeters. Its size is extraordinary compared with the relatively small gemstones normally seen in jewelry.
8. Topaz is sometimes confused with quartz
Some historical and trade names can make topaz and quartz rather confusing. "Topaz quartz" is actually citrine, while "smoky topaz" and "burnt topaz" are names that have been used for brown quartz.
Topaz and quartz are completely different minerals. The confusion probably developed partly because some varieties of quartz and topaz can have similar yellow, golden or brown colors. GIA specifically recommends being cautious about these misleading names.
9. Topaz is a fluorine-containing mineral
Topaz has the chemical formula Al₂(F,OH)₂SiO₄, meaning that its structure contains aluminum, silicon, oxygen and fluorine and/or hydroxyl groups. It belongs to the orthorhombic crystal system and commonly forms elongated, prismatic crystals.
The crystals often have grooves running parallel to their length. Their shape can influence how rough topaz is cut, with elongated ovals and pear shapes being particularly suitable for many crystals.
10. Brazil is an important source of topaz
Brazil has long been one of the world's most important sources of topaz, particularly the famous Ouro Prêto (Ouro Preto) region of Minas Gerais. This area is especially associated with Imperial topaz.
Topaz is found in several other countries too, including the United States, Pakistan, Madagascar, Mexico, Nigeria, Namibia, Australia and Sri Lanka. In the United States, topaz is particularly associated with Texas and Utah, and topaz is the official state gemstone of Texas.
November Month Quiz
As you may know Topaz is one of the gemstones of November together with Citrine and other symbols of November. Here is a fun trivia quiz about the month of November.
No email is required - your score and the answers will come up here after you hit the Submit button :).
