Gemology Hub | Gemstone & Mineral Identification Guides

  Most Expensive Emeralds Ever Sold Emeralds are one of the most valuable and rare gemstones in the world, prized for their beautiful green color and high level of durability. Over the years, some emeralds have sold for extraordinary prices, reaching into the millions of dollars. In this article, we'll take a closer look at the most expensive emeralds ever sold, who bought them, and where they came from. Emerald Price (USD) Buyer Origin Current Location Teodora $12.6 million Unknown Zambia Private Collection Rockefeller Emerald $305 million Laurence Graff Colombia Private Collection Mogul Mughal Emerald $2.2 million Anonymous Colombia Unknown Gachala Emerald $1.5 million Harry Winston Colombia Smithsonian Museum of Natural History Duke of Devonshire Emerald $1.3 million Unknown Colombia Private Collection As you can see, the most expensive emeralds ever sold have all come from Colombia, which is known for producing some of the finest emeralds in the world. These emeralds are highly...

  Kyanite Information Kyanite is a mineral that is typically blue in color and is used as a gemstone, although it can also be found in other colors such as green, orange, and black. Kyanite has a unique and interesting crystal structure that is highly valued in the gemstone industry. Physical Properties Color: Blue, Green, Orange, Black Hardness: 4.5-7.0 Luster: Vitreous to pearly Streak: White Transparency: Transparent to translucent Cleavage: Perfect, parallel to the length of the crystal Fracture: Splintery to fibrous Specific Gravity: 3.53-3.65 Optical Properties Refractive Index: 1.712-1.734 Birefringence: 0.018-0.029 Optic Character: Biaxial negative Pleochroism: Strong Localities United States: North Carolina, Connecticut, Georgia, Montana, Virginia, Wyoming Brazil Switzerland Austria Myanmar Kenya India Australia Ranking in Rarity Kyanite is considered a rare gemstone, with the most prized specimens being those that are blue in color and have a high degree of transparency. ...

  Yellow Topaz from Germany According to a recent report in the Spring 2022 issue of  Gems & Gemology , yellow topaz from Germany has been found to have high levels of the trace element chromium. This discovery has important implications for gemological research, as it may help to distinguish German topaz from other sources. The researchers who conducted the study found that yellow topaz from Germany typically contains 200 to 500 parts per million (ppm) chromium, while topaz from other sources typically contains less than 100 ppm chromium. The researchers also noted that the chromium in German topaz is likely to be in the form of Cr 3+ , which is responsible for the gemstone's yellow color. In addition to its scientific significance, German topaz is also highly valued by collectors and jewelry enthusiasts for its unique color and clarity. The gemstone is typically found in small sizes (less than 5 carats), but is prized for its intense yellow hue and brilliant sparkle. If ...

Vesuvanite Information Types Vesuvianite, also known as idocrase, is a mineral with a complex chemical formula. It can have various colors, including green, yellow, brown, and blue. Some varieties include: California Jade - a green vesuvianite found in California, USA Chrome Vesuvianite - a green vesuvianite colored by chromium Magadi-type Vesuvianite - a blue variety found in Tanzania Wiluite - a yellow vesuvianite found in California, USA Localities Vesuvianite can be found in various locations around the world, including: Canada Italy Japan Kenya Mexico Tanzania USA Physical Properties Vesuvianite has a hardness of 6.5 on the Mohs scale and a specific gravity of 3.3-3.5. It has a vitreous to resinous luster and can be transparent to opaque. Its crystal structure is tetragonal. Optical Properties Vesuvianite has a uniaxial positive optical character and a refractive index of 1.700-1.750. It can exhibit pleochroism and dispersion. Healing Properties Vesuvianite is said to have various...

  Rhodonite Rhodonite is a mineral with the chemical composition MnSiO3 and a hardness of 5.5 to 6.5 on the Mohs scale. It is found in metamorphic rocks and is often used as a gemstone. Localities Rhodonite can be found in many countries around the world, including: Australia Canada Madagascar Mexico Peru Russia Sweden United States Physical Properties Rhodonite has the following physical properties: Color: rose pink to brownish red Luster: vitreous to dull Streak: white Transparency: opaque to translucent Specific Gravity: 3.57 to 3.76 Optical Properties Rhodonite has the following optical properties: Refractive Index: 1.734 to 1.766 Birefringence: 0.032 to 0.036 Pleochroism: weak to strong Healing Properties Rhodonite is believed to have the following healing properties: Helping to heal emotional wounds Reducing stress and anxiety Improving confidence and self-esteem Enhancing intuition and spiritual awareness Uses Rhodonite is primarily used as a gemstone, but it also has other ...

Taaffeite Details  History Taaffeite was first discovered in 1945 by a gemologist named Richard Taaffe. At the time, he thought the mineral was a spinel, but it was later identified as a new mineral species. Taaffeite is a rare mineral and was only found in a few locations around the world. It was first discovered in Sri Lanka and later found in Tanzania, China, and Madagascar. For many years, taaffeite was considered to be one of the rarest gemstones in the world. Its rarity and beauty have made it a popular choice for collectors and jewelry designers. Physical and Optical Properties Taaffeite has a chemical composition of Mg3Al8BeO16 and a Mohs hardness of 8.5, which makes it a durable gemstone. It has a refractive index of 1.719-1.720 and a specific gravity of 3.60-3.62. Taaffeite is usually found in colors such as lavender, mauve, and violet. Under ultraviolet light, taaffeite can show a strong fluorescence. It can also show pleochroism, which means that it can appear different...

  Azurite Mineral History Azurite is a copper carbonate mineral that has been known since ancient times. The name "azurite" comes from the Persian word "lazhward", which means blue. It was used in ancient Egypt and Greece as a pigment for painting and in jewelry making. Azurite was also used by the ancient Chinese and Native Americans for ornamental and medicinal purposes. Discovery Azurite is found in copper deposits worldwide, especially in areas with arid climates like Arizona, New Mexico, and Utah in the United States. It is often found in association with malachite, another copper carbonate mineral. Azurite was first described scientifically in 1824 by the French mineralogist François Sulpice Beudant. Chemical formula & Physical Properties Chemical Formula Cu3(CO3)2(OH)2 Color Azure blue Crystal System Monoclinic Hardness 3.5 - 4 Luster Vitreous Streak Light blue Optical Properties Azurite is a pleochroic mineral, which means that it shows different colors ...

  Tawmawite Properties Tawmawite is a rare mineral that has several unique properties. It is a silicate mineral and has the chemical formula of Cu6Hg3As4S12. It was discovered in 1974 in the Tawmaw mine in northern Shan State, Myanmar. Tawmawite is a member of the enargite family, which is composed of copper arsenic sulfides. It is named after the Tawmaw mine where it was first discovered. Physical Properties Color: black, dark brownish-black Luster: metallic Streak: black Hardness: 3 on the Mohs scale Density: 5.95 g/cm3 Cleavage: {100} good, {010} fair, {001} poor Optical Properties Transparency: opaque Refractive Index: n = 2.58 - 2.88 Birefringence: none Pleochroism: none Ranking of Rarity Tawmawite is an extremely rare mineral and is considered to be one of the rarest minerals in the world. Occurrence (countries) Tawmawite has only been found in the Tawmaw mine in northern Shan State, Myanmar. It has not been found in any other locations around the world. Healing Properties Th...

Clinozoisite Overview Clinozoisite is a mineral that belongs to the epidote group and has the chemical formula Ca 2 Al 3 Si 3 O 12 (OH). Varieties Clinozoisite has a few different varieties, including: Clinothulite Thulite Chemical Formula The chemical formula for clinozoisite is Ca 2 Al 3 Si 3 O 12 (OH). Physical Properties Color: Green, brown, gray, white, pink, red, blue Crystal System: Monoclinic Hardness: 6.5 - 7 Cleavage: Good in one direction Luster: Vitreous Streak: White Optical Properties Refractive Index: 1.707 - 1.725 Birefringence: 0.018 - 0.019 Optical Character: Biaxial positive Dispersion: Weak Ranking of Rarity Clinozoisite is not a particularly rare mineral, and can be found in many locations around the world. Occurrence (Countries) Clinozoisite can be found in the following countries: Switzerland Italy Germany Austria USA Canada Chile Peru Russia China Japan Healing Properties Clinozoisite is said to have the following healing properties: Helps to reduce stress and a...

  Zoisite Zoisite is a mineral belonging to the sorosilicate family. It has the chemical formula Ca2Al3(SiO4)3(OH), and it is often found in a variety of colors and forms. Here is some more information about zoisite: Varieties Zoisite comes in a variety of colors and forms. Some of the most well-known varieties include: Tanzanite - blue to violet-blue zoisite, first discovered in Tanzania in 1967 Thulite - pink to reddish-pink zoisite, first discovered in Norway in 1820 Anyolite - green zoisite with ruby inclusions, first discovered in Tanzania in the 1950s Discovery Zoisite was first discovered in Austria in 1805 by the mineralogist Sigmund Zois. Since then, zoisite has been found in many locations around the world. Physical Properties Hardness: 6.5 - 7 Density: 3.15 - 3.36 g/cm3 Color: Typically brown, green, or pink, but can also be blue, violet-blue, or colorless Luster: Vitreous to subadamantine Streak: White Optical Properties Refractive index: 1.69 - 1.70 Birefringence: 0.00...

  Piemontite Information Piemontite is a mineral species that belongs to the epidote group. It was first discovered in the Piedmont region of Italy, and was named after its place of discovery. Here is some information about piemontite: Physical Properties Chemical formula: Ca2Fe3+Al2(SiO4)(Si2O7)O(OH) Color: brown, reddish brown, greenish brown, black Hardness: 6.5 - 7 on the Mohs scale Luster: vitreous to subresinous Streak: yellow-brown to orange-brown Optical Properties Refractive index: nα = 1.734 - 1.743, nβ = 1.735 - 1.745, nγ = 1.745 - 1.755 Birefringence: δ = 0.011 - 0.012 Pleochroism: weak, yellowish brown to reddish brown Ranking of Rarity Piemontite is a relatively rare mineral, and is not commonly found in large quantities. It is ranked as a 7 out of 10 on the rarity scale. Occurrence (countries) Piemontite can be found in several countries around the world, including: Italy Switzerland USA Canada Japan New Zealand Tanzania Healing Properties Piemontite is believed to h...