Imperial topaz

Imperial topaz is the trade name for natural topaz in orange, reddish orange, pink and red. According to GIA, its only known commercial source is the Ouro Preto area in the Brazilian state of Minas Gerais, where topaz has been mined for more than 200 years. Pinks, reds and purplish tones come from traces of chromium in the crystal; yellows and oranges come from defects in the crystal structure called colour centres. The name has no fixed standard; in GIA's words, it is the colour, not the term “imperial”, that gives topaz its value.

Jewellery: hard and brilliant, it is used as a precious stone in rings, necklaces and earrings. Commercial sizes are mostly 2–8 carats; stones of 20–30 carats are rare. Museums and collecting: large, well-coloured stones are displayed in museums. In 2018 the Smithsonian Institution added the vivid red, 48.86-carat “Whitney Flame” topaz to its collection. History: stones from Ouro Preto were set in church and court jewellery in Portugal by the mid-18th century, and in the 19th century imperial topaz became a recognised product on the European gem market.

It has a hardness of 8 on the Mohs scale. It scratches glass and steel; a steel knife cannot scratch it. Its specific gravity is 3.49–3.57 g/cm³.

Its best-known localities: Capão mine, Rodrigo Silva, Ouro Preto, Minas Gerais, Brazil; Vermelhão (Saramenha) mine, Ouro Preto, Minas Gerais, Brazil; Ural Mountains, Russia; Ghundao Hill, Katlang, Mardan, Pakistan; Nigeria.

As a topaz it is very hard (8) and scratches quartz. But it has perfect cleavage parallel to its base, so a hard knock can split it along a smooth plane. Its colour can change with the viewing direction (pleochroism): yellow, yellowish orange and reddish pink may all show in one stone, so the cutter orients the stone to give the best colour. Its specific gravity is about 3.5, so it feels clearly heavier than a citrine of the same size (about 2.65). Heat-treated pink topaz: some brownish-yellow or orange topaz turns peach or pink when heated to about 565 °C. This is a common and accepted treatment, but such stones sell for less than naturally pink ones and must be disclosed.

On the “street to diamond” value ladder it sits on step 7 of nine: Precious stone. Colour matters most for imperial topaz: saturated reddish orange, sherry red and natural pink are the most sought after, while pale yellow and brownish stones are cheaper. Value per carat rises markedly above 2, 5 and 10 carats; large, clean red stones are very rare. Stones heated to pink are worth less than naturally pink ones and must be disclosed. Because “imperial” has no official definition, what counts is that the seller documents the stone's actual colour and any treatment rather than the name.

Today crystal-therapy websites claim that imperial topaz is linked to the sacral and solar plexus chakras, gives confidence, determination and creativity, and attracts abundance. The same websites say the stone relieves stress and anxiety and evens out emotional ups and downs. There is no scientific evidence that imperial topaz brings confidence, creativity or abundance, or that it relieves stress; persistent anxiety or mood problems call for a doctor. The stone's warm colour comes from traces of chromium and from small defects in its crystal structure. This section reports beliefs; it is not health information. There is no scientific evidence for these claims and no stone replaces medical treatment.