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Mineral topaz is very abundant in Brazil. The Rio de Janeiro Museum contains an 10,000-carat imperial topaz.
Imperial topaz is a beautiful stone and got its name, possibly from Topázio Island in the Red Sea. There, these stones were quite common in the Middle Ages.
Thus, the color of the stone is generally not very bright, mainly yellow-orange. But the imperial topaz is distinguished by its pink (orange-pink) color.
Brazil is the largest supplier of beautiful stones such as Imperial Topaz.
For example, at the Imperial mine, near Ouro Preto. Therefore, about 40 kilos of stone are removed each month. And only 600 grams are processed. But few crystals exceed 4 centimeters.
However, related minerals have little or no economic value as crystal specimens.
But this stone is also found in Zimbabwe, Sri Lanka, Russia, Pakistan, Nigeria, Namibia, Mexico, Madagascar, Japan, China, USA, Burma, Australia, Northern Ireland, Scotland. But in 1964, a hundred kilograms were found in Ukraine.
What is Imperial Topaz?
From a mineralogical point of view, topaz is an aluminum silicate fluid hydrate that is colored by the elements iron and chromium. Thus, in some cases, treated to produce a wide variety of colors.
But topaz goes back to a long history:
Mention is made of the topaz, as one of the “stones of fire” (Ezekiel 28, 13-16). ANDlas they were presented to Moses on the mountain and by God’s instruction (Exodus 28, 15-30) they were inserted into Aaron’s breastplate (high priest and brother of Moses).
Furthermore, in the Apocalypse of John (21, 1921), the topaz is one of the twelve precious stones that adorn the fundamental stones of the heavenly Jerusalem wall (Revelation 21:19).
Characteristics of Imperial Topaz
In addition, imperial topaz is known as “precious topaz”. Therefore, it is the most sought after natural topaz.
But the imperial topaz is transparent to translucent. It displays high clarity with few inclusions, so topaz gems can be examined with the naked eye and considered “clean”, meaning that no imperfections can be seen. Thus, it is highly valued for its brilliance.
Cut and shape
In addition, imperial topaz is a very versatile material. Therefore, it can be cut into a wide variety of shapes, such as square, round, octagon, pear, oval, heart and even fancy shapes.
So, the hardness makes it scratch resistant. However, lapidators must handle the topaz with care due to its perfect cleavage, which means that it can fracture easily.
Treatment
In addition, imperial topaz is generally not treated or improved. However, orange-brown is heat treated during a process known as “pink”, which produces a purple pink color.
Gemological Properties of Imperial Topaz:
| Chemical formula: | Al2SiO4 (F, OH) 2 Fluor containing aluminum silicate |
| Crystal structure: | Orthorhombic, prisms with multifaceted ends, especially octagonal in cross section |
| Color: | Yellow, pink, pink-orange, orange or red overcoat |
| Toughness: | 8 on the Mohs scale |
| Refractive index: | 1,609 – 1,643 |
| Density: | 3.49 – 3.57 |
| Cleavage: | Perfect |
| Transparency: | Transparent and translucent overcoat |
| Double refraction or birefringence: | 0.008 to 0.016 |
| Brightness: | Vitreous |
| Fluorescence: | Under long wavelength UV, pink and yellow. Thus, they can show a strong orange-yellow glow; red shows a faint yellow-brown glow |
