Jadeite is most famous for its gem form of Jade . Jewelry and ornamental carvings wer... More
Jadeite is most famous for its gem form of Jade. Jewelry and ornamental carvings were made from Jade throughout history. Jade was very precious in some ancient societies, and was sometimes worth even more than Gold.
Jadeite is not the only form of Jade; the amphibole mineral Nephrite (a variety of Actinolite) also has a gem form of Jade. On a gemological standpoint, all tough masses of Jadeite and Nephrite are called Jade. The Jadeite and Nephrite forms of Jade are almost identical, and it may be very difficult to distinguish the two. In fact, they were thought to be one mineral type until 1863, when it was discovered that they are scientifically different minerals.
Jadeite Jade is the rarer and more valuable form of Jade. The most common color for both forms of Jade is pale green. Emerald-green Jade, known as Imperial Jade, is the most valuable form of Jade. Jadeite is rarely represented in mineral collections, since it is usually uninteresting in its rough form and commercially mined only for gemstone use. Hide
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div Jamesonite nbsp typically forms in a unique crystal habit of fine acicular crysta... More
Jamesonite typically forms in a unique crystal habit of fine acicular crystals that appear as woven, hair-like fibers. It may also form as dense, hairy inclusions within other crystals, such as Calcite, Fluorite, and Barite. Jamesonite often forms together with the chemically similar mineral Boulangerite, and it may be very difficult to visually distinguish these two minerals. Jamesonite is named after Robert Jameson (1774-1854), a Scottish mineralogist.
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div Jarosite is both an individual mineral, as well a group name of several similar m... More
Jarosite is both an individual mineral, as well a group name of several similar minerals. Jarosite is the most common member of the group; some of the other rare members include Ammoniojarosite, Argentojarosite, Beaverite, Dorallcharite, Hydroniumjarosite, Natrojarosite, and Plumbojarosite.
Jarosite was first described in 1852 by German mineralogist August Breithaupt in type locality of Barranco Jaroso in the Sierra Almagrera in Southern Spain. In 2004, it was detected by the exploration rover Opportunity on Mars, indicating the possible presence of water that once existed on Mars.
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Jasper is an opaque form of Chalcedony , which is a microcrystalline variety of the m... More
Jasper is an opaque form of Chalcedony, which is a
microcrystalline variety of the mineral Quartz. It often contains an abundance of impurities, and therefore some regard it as a rock instead of a mineral. Jasper is usually associated with brown, yellow, or reddish colors, but may be used to describe other opaque colors of Chalcedony such as dark or mottled green and orange. Some forms of Jasper are banded, and these banded Jaspers may appear similar to Agate, but unlike Agate they are opaque. When Jasper is dull and lacking interesting colors or patterns, it is not Jasper but rather Chert. For additional information, see the gemstone section on Jasper. Hide
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div Jeremejevite is a rare borate mineral, best known for its aesthetic blue and gemm... More
Jeremejevite is a rare borate mineral, best known for its aesthetic blue and gemmy crystals. It is one of the more difficult minerals to pronounce; the correct pronunciation is "Yeremiyaivite." Jeremejevite was first described in Siberia in 1883, and is named after Russian mineralogist Pavel Vladimirovich Jeremejev (1830–1899). The last name is Germanized from the Russian "Eremeev".
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Johannsenite is a rare member of the pyroxene group that is isomorphous with Diopside... More
Johannsenite is a rare member of the pyroxene group that is isomorphous with Diopside and Hedenbergite. It often occurs with black manganese oxide dendrites on its surface. Johannsenite alters to become the pink mineral Rhodonite. Johannsenite is named in honor of Albert Johannsen (1871-1962), a petrologist and professor at the University of Chicago. Hide
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