Chemistry of the mineral Topaz
Topaz is a silicate mineral which is the largest and most important class of rock-forming minerals. Topaz belongs to the sub-class Nesosilicates, the simplest of all silicates in which the tetrahedral SiO4 units exist separately, but are held together by metal cations as in Garnets, Andalusite and Olivine, or form cross linkages between chains of octahedrally co-ordinated aluminum cations, such as AlO4F2, AlO4F(OH), and AlO4(OH)2 , as in Topaz. The crystalline shape of topaz is caused by the octahedral chains, and the strong bonds and close packing of atoms and ions give topaz a higher density, refractive index and hardness relative to other subclasses of silicates. Topaz is also one of the few gem minerals that can grow to enormous sizes given the appropriate conditions, and some crystals can grow to massive sizes of up to several hundred kilograms.
This web page is devoted to notable topaz gemstones both cut and uncut that had attained international fame, primarily due to their enormous sizes, and exhibited as part of mineral collections in renowned museums around the world.
1) The American Golden Topaz
This is the 3rd largest faceted topaz and perhaps the 3rd largest faceted gemstone in the world, weighing a massive 22,892.5 carats (4.5785 kg), with a cushion-cut having 172 facets. The combination of perfect cut, clarity, and color makes the gemstone one of the most renowned faceted gemstones in the world. The gemstone which is of Brazilian origin is exhibited in the Hall of Geology, Gems and Minerals of the National Museum of Natural History of the Smithsonian Institution. Please click here for more information on the American Golden Topaz.
2) The Golden Topaz Sphere
The Golden Topaz Sphere is a faceted, golden topaz, with a spherical-cut and weighing a whopping 12,555 carats. The color, cut and clarity of the gemstone are exceptional. The enormous gemstone appears to be of Brazilian origin, like its counterpart the American Golden Topaz, both of which are exhibited side by side, in the National Museum of Natural History of the Smithsonian Institution, in Washington DC. Readers who may have more information pertaining to the gemstone, such as the date of discovery, the original owner of the gemstone, the date the gemstone was acquired by or donated to the Smithsonian Institution, the identity of the cutter of the gemstone etc. are kindly requested to post the same as comments to this page.
3) The Lindsay Uncut Topaz
The Lindsay Uncut Topaz is another prominent exhibit in the Smithsonian’s gem and mineral collection, exhibited in the Hall of Geology, Gems and Minerals. The uncut rough stone is a short vertically striated prismatic crystal terminated by a pyramidal face, and weighs an enormous 32 kg equivalent to 70 lbs. The source of this crystal like most other massive topaz crystals is undoubtedly the mineral-rich state of Minas Gerais in southeastern region of Brazil.
Readers who may have more information on the Lindsay Uncut Topaz, such as the origin of the name Lindsay, the date of acquiring or donation of the crystal to the institution etc. are requested to post the same as comments to this page.
4) The Freeman Uncut Topaz
The Freeman Uncut Topaz is yet another massive crystal belonging to the Smithsonian’s Gem and Mineral Collection, considered to be one of the most comprehensive collections of its kind in the world, consisting of around 350,000 mineral specimens, 300,000 rock and ore specimens, and 15,000 individual gems. Besides the collection also includes around 35,000 meteorites, thus making it one of the most unique collections in the world.
The Freeman Uncut Topaz is also a vertically striated prismatic crystal terminated by a pyramidal face like the Lindsay Uncut Topaz, but somewhat taller than the latter. The greater height of the crystal is also reflected in its weight, which is equivalent to a massive 50.5 kg or 111 lbs, as compared to the weight of 32 kg of the Lindsay Uncut Topaz. The Freeman Uncut Topaz also seems to have originated in the topaz mines of Minas Gerais, the mineral-rich state in southeastern Brazil.
Readers who may have more information on the Freeman Uncut Topaz are requested to post the same as comments to this page.
5) El-Dorado Topaz
The “El-Dorado Topaz” is the largest faceted topaz and the largest faceted gemstone in the world, weighing a whopping 31,000 carats equivalent 6.2 kg. It exceeds the weight of the faceted “American Golden Topaz” by about 8,100 carats. Like the “American Golden Topaz,” the “El-Dorado Topaz” also originated in the mineral-rich southeastern state of Brazil, Minas Gerais, the premier source of enormous topaz crystals in the world. The rough “El-Dorado” crystal weighed an astonishing 37 kg, when discovered in 1984, and after cutting and polishing weighed only 6.2 kg. The enormous loss of 30.8 kg during processing can be attributed to the poor gem-quality material that had to be removed in order to come up with a finished product of perfect cut, clarity and color. The completed gemstone is indeed an exceptional product with a perfect emerald-cut, good clarity and a yellowish-brown color. The “El-Dorado Topaz” is part of the Special Exhibitions Gem Collection of the Programa Royal Collections Group, an European Economic Interest Group founded in 1997 to create large-scale collections of Gemology, Art and Science, which were meant to serve as the basis of cultural tourism projects. Please click here for more information on the “El-Dorado Topaz.”
6) “Lua de Maraba” Topaz
The “Lua de Maraba” Topaz, which in the Portuguese language means “Moon of Maraba” is the second largest faceted topaz in the world, as well as in the Special Exhibitions Gem Collection of the Programa Royal Collections Group, based in Madrid, Spain. The stone which has a beautiful octagonal-cut has dimensions of 18 x 15 x 10 cm, and is of Brazilian origin. The faceted stone that weighs 25,250 carats has a rare grey color, perhaps the only one of its color and size in the world. The topaz collection of the Programa Royal Collections (PRC) is undoubtedly the largest and most comprehensive collection of topaz in the world, consisting of 54 gemstones of all colors, cuts and sizes totaling more than 90,000 carats. This collection also includes eight gemstones varying in size from 1,800 carats to 31,000 carats, perhaps the largest collection of enormous faceted topaz gemstones in the world. Please click here for more information on this topaz.
7) Topaz Amarelo (Yellow Topaz)
The “Topaz Amarelo” is the third largest faceted topaz in the topaz collection of the Programa Royal Collections (PRC) after the 31,000-carat “El-Dorado Topaz” and the 25,250-carat “Lua de Maraba Topaz.” Amarelo in the Portuguese Language means yellow color. The “Topaz Amarelo” is a yellow topaz of Brazilian origin. The faceted gemstone is a pear-shaped yellow topaz weighing 9,600 carats, and perhaps the largest pear-shaped topaz in the world. The color, cut and clarity of the stone is exceptional, worthy of being part of the prestigious collection, known as the Programa Royal Collections, put together by an European Economic Interest Group founded in 1997, to create large-scale collections of Gemology, Art and Science, to promote cultural tourism projects, and based in Madrid, Spain. The “Topaz Amarelo” is one of the 20 precious stones of extraordinary sizes and gemological quality, brought together under the category, “Special Exhibition Gems.” Please click here for more information on this topaz.
8) Topaz Azul (Blue Topaz)
Azul in the Portuguese language means blue. Thus “Topaz Azul” refers to a blue topaz. The “Topaz Azul” is the 4th largest topaz in the topaz collection of the of the Programa Royal Collections (PRC), which consist of 54 topaz gemstones weighing 90,000 carats and belonging to all colors, cuts and sizes. The topaz collection of the PRC, is undoubtedly the world’s largest and most comprehensive collection.
The “Topaz Azul” which is of Brazilian origin, is an enormous 8225-carat cushion-cut topaz with good clarity and originally colorless, yellow or yellowish-brown . The massive gemstone was subjected to irradiation by one of the following methods :- ultraviolet rays, x-rays, gamma rays, high energy electrons, and the stone acquired a permanent intense blue color. Gamma irradiation is the common method employed in this process. The blue color is caused by the permanent “color centers” created by irradiation, which are stable like the color centers of natural blue topaz, and therefore does not fade in light. The 8225-carat “Topaz Azul” is perhaps the largest irradiated blue topaz in the world. Please click here for more information on this topaz.
9) The Braganza “Diamond”
The legendary 1640-carat colorless Braganza “Diamond” is said to have been discovered in Minas Gerais in 1740, just a few years after diamonds were discovered in the village of Diamantina in the region. During this period mining was under the tight control of the Portuguese colonialists, and extraordinarily large diamonds usually entered the crown jewels of the Portuguese Monarchy. Accordingly the enormous Braganza “Diamond” entered the crown jewels of the King of Portugal. King John VI of Portugal who reigned between 1816 and 1826, is reported to have worn the Braganza “Diamond” as a rough suspended gem. The diamond apparently disappeared after this, but according to Dr. J. Kourimsky, the cut and polished Braganza “Diamond” was later set on the Portuguese crown. It was eventually discovered that the Braganza “Diamond” which was previously believed to be a diamond, was actually a massive colorless topaz, for which Minas Gerais subsequently became renowned as the world’s premier source of such enormous topaz gemstones. Please click here for more information on this topaz.
10) The Brazilian Princess Topaz
The 21,005-carat “Brazilian Princess Topaz” exhibited at the J. P. Morgan Hall of Gems of the American Museum of Natural History, at New York City, was at one time considered to be the World’s largest faceted gemstone, but has now been pushed to the 4th place. Presently, the World’s first and second largest faceted gemstones are the 31,000-carat “El-Dorado Topaz” and the 25,250-carat “Lua de Maraba Topaz” belonging to the Programa Royal Collections, based in Madrid, Spain. The 22,892.5-carat American Golden Topaz displayed at the Smithsonian’s National Museum of Natural History, is the 3rd largest faceted gemstone in the world. The “Brazilian Princess Topaz” is yet the largest faceted blue topaz in the world.
The “Brazilian Princess Topaz” is a square emerald-cut, light blue sapphire of good clarity and as the name indicates of Brazilian origin. Natural blue topaz is very rare and one of the sources of this rare variety of topaz is the Ural Mountains of Russia. The Mining College Museum in St. Petersburg, Russia, is reported to be holding a giant blue topaz recovered from Murzinka, in the Urals. Most of the topaz mined in Brazil are the colorless, yellow, and yellowish-brown varieties, and rarely the pink and red varieties. The occurrence of natural blue topaz in Brazil is extremely rare. Thus, the chances of the enormous 21,005-carat ‘Brazilian Princess Topaz” being a natural blue topaz is extremely rare.
11) Other massive topaz gemstones about which more information is needed
a) A 3273-carat blue topaz in the NMNH of the Smithsonian Institution.
b) A 1469-carat yellow-green topaz also belonging to the NMNH of the Smithsonian Institution.
c) A 150 kg natural pink topaz crystal discovered in Minas Gerais, and presently displayed at the Mineralogical Institute, Florence, Italy.
d) A rare natural blue topaz weighing 100 kg discovered in 1965 in the Ural Mountains of Russia.
e) A two feet long, 137 lb (62.3 kg), topaz crystal discovered in Norway in 1901.
f) A 600 lb (273 kg) topaz crystal discovered in Brazil, and belonging to the AMNH, New York.
g) A 9000-carat orange topaz crystal of Brazilian origin, displayed at the Los Angles County Museum of Natural History.
h) A 7725-carat yellow topaz displayed at the Smithsonian’s NMNH.
i) A 4202-carat emerald-cut colorless topaz belonging to the Programa Royal Collections.
j) A 2915-carat oval-cut colorless topaz of the Programa Royal Collections.
k) A 1833-carat pear-shaped blue topaz of the Programa Royal Collection.
l) A 1800-carat oval-shaped blue topaz also of the Programa Royal Collection.
Readers who may have more information on any one of the above topaz gemstones are kindly requested to post such information as comments, in order to make this web page devoted to “Famous Cut & Uncut Topaz Gemstones” as comprehensive as possible.
Readers who might have come across large and famous topaz gemstones not mentioned on this page are welcome to upload photos and descriptions of such stones at this link
1) Topaz – A Neosilicate – Edna B, Anthony – The New Mexico Facetor.
2) Gem & Crystal Treasures – Peter Bancroft.
3) American Museum of Natural History – Wikipedia, the free encyclopedia.
4) Website of Programa Royal Collections – Madrid, Spain.