Topaz gemstone has a glassy luster and is often exceptionally pure. It is highly electrified by friction. Weak fluorescence is observed in ultraviolet rays.
Shades of topaz
Topaz is often completely colorless or very faintly colored. Yellow shades of various densities are often observed: from pale yellow to thick cherry-brown tones.
There are pure blue topaz and pale green stones mistaken for aquamarines. Red and pink stones are very rare in nature. The beautiful pink topaz, which has long attracted the attention of jewelers, is obtained from Brazilian brownish-yellow stones by heating. This color occurs when heated stones are cooled and does not appear to fade when exposed to sunlight, as is common with many pink minerals.
It is fairly easy to reproduce this discoloration. One passionate collector loved to surprise and entertain his guests by placing a crucible of fireproof powder containing a suitable crystal of topaz stone in the fireplace and removing a pink crystal from the crucible after dinner. Heating causes some redistribution of the atoms composing the crystal, since all pink topaz, while retaining the previous crystal shape, have high refractive indices and pronounced dichroism. At the same time, foreign atoms diffuse into the crystal and cause the appearance of different color shades. By the way, not all yellow topaz turns pink when heated.
So, topaz from Ceylon are discolored. Pale yellowish-brown crystals from the Urulga River (Russia) fade with prolonged exposure to bright sunlight.
Separately, it should be said about Brazilian topaz: stones of such piercing and bright orange tones are not found anywhere else in the world. So the name “Imperial” and a place of honor among the best gemstones are justified.
Prices for topaz of different colors
Due to the variety of color palette and low cost, topaz is very popular among jewelers. Most topaz, intended for jewellery making, undergo a refining procedure, which consists in irradiation and heat treatment of crystals to give them a richer color. Despite the fact that refined stones look much brighter and more spectacular, their cost is reduced.
The most expensive are natural topaz in rich pink and purple tones. Also appreciated are blue, yellow, golden brown stones. Diamond and emerald cut topazes are most often used in jewellery. Large collectible items are marketed in the form of cabochons or without processing at all.
Did you know that …
The world’s largest processed yellow topaz is American Gold Topaz. Its weight is 22,892 carats (about 4.5 kilograms), and it took 2 years to cut the stone.
The 1,680-carat topaz gemstone, named after Braganza, is part of the treasures of the Portuguese crown. For many years, this stone was officially considered a huge diamond.
Topaz of the color mystic or nitrogen does not exist in nature. The stones get their color due to a specific coating, which wears off over time.