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Grape Agate is a market name for purple aggregates of tiny quartz crystals with botryoidal (spherical) habit. [1] Mineralogically speaking, grape agate is not an agate [2] and is actually botryoidal purple chalcedony. [3] It occurs in Indonesia [2] and has also been found west of the Green river in Utah. [4]: 75
A synthetic quartz crystal grown by the hydrothermal method, about 19 centimetres (7.5 in) long and weighing about 127 grams (4.5 oz) Not all varieties of quartz are naturally occurring. Some clear quartz crystals can be treated using heat or gamma-irradiation to induce color where it would not otherwise have occurred naturally. Susceptibility ...
Cape May diamonds range in size from the finest sand to a 3-pound-14-ounce (1.8 kg) "Cape May diamond" found in New Castle, Delaware in 1866. [1] In the 1960s a small intact quartz crystal was found at Sunset Beach which showed almost no signs of rounding by erosion.
The geodes containing the Bristol Diamonds are frequently found in this conglomerate, in the areas of Bridge Valley Road, Leigh Woods, Sea Mills and St Vincent's Rocks. [ 6 ] [ 7 ] [ 8 ] The geodes were formed from quartz, either megaquartz or fibrous quartz, the diamonds themselves resulting from the dissolution of nodules of anhydrite leaving ...
Prasiolite (also known as green quartz, green amethyst or vermarine) is a green variety of quartz. Since 1950, almost all natural prasiolite has come from a small Brazilian mine, [citation needed] but it has also been mined in the Lower Silesia region of Poland. Naturally occurring prasiolite has also been found in the Thunder Bay area of ...
Inclusions can be found in these crystals that provide clues to the origins of the Herkimer diamonds. Found within the inclusions are solids, liquids (salt water or petroleum), gases (most often carbon dioxide), two- and three-phase inclusions, and negative (uniaxial) crystals. A black hydrocarbon is the most common solid inclusion.
Quartzite is a very hard rock composed predominantly of an interlocking mosaic of quartz crystals. The grainy, sandpaper-like surface is glassy in appearance. Minor amounts of former cementing materials, iron oxide, silica, carbonate and clay, often migrate during recrystallization, causing streaks and lenses to form within the quartzite. [1]
Quartz crystals with masses measured in thousands of pounds [5] and micas over 10 meters (33 ft) across and 4 meters (13 ft) thick have been found. [8] Spodumene crystals over 12 meters (40 ft) long have been found in the Black Hills of South Dakota , and beryl crystals 8.2 meters (27 ft) long and 1.8 meters (6 ft) in diameter have been found ...