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2. Quartz - Wikipedia

   en.wikipedia.org/wiki/Quartz

   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 ...

3. Tourmaline - Wikipedia

   en.wikipedia.org/wiki/Tourmaline

   Tri-chromatic elbaite crystals on quartz, Himalaya Mine, San Diego Co., California, US. Tourmaline is a six-member ring cyclosilicate having a trigonal crystal system. It occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section, often with curved striated faces. The style of termination at ...

4. Inclusion (mineral) - Wikipedia

   en.wikipedia.org/wiki/Inclusion_(mineral)

   The term three phase relates to the three phases of matter, solid, liquid, and gas. This is a three phase inclusion in rock crystal quartz. The solid is a black material that is of bituminous origin. The liquid encased is petroleum, and the gas bubble is methane. Inclusions are one of the most important factors when it comes to gem valuation.

5. Pegmatite - Wikipedia

   en.wikipedia.org/wiki/Pegmatite

   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 ...

6. S-type granite - Wikipedia

   en.wikipedia.org/wiki/S-type_granite

   For example, apatite occurs in S-type granites in greater modal abundance and as larger, discrete crystals than in the I-type granites. [1] [4] Figure 5a, 5b, and 5c show the mineral tourmaline associated with quartz in sample CV-114 from the Strathbogie Granite, Australia.

7. Luxullianite - Wikipedia

   en.wikipedia.org/wiki/Luxullianite

   Luxullianite (also known as luxulyanite or luxulianite) is a rare type of porphyritic granite, notable for the presence of clusters of radially-arranged acicular tourmaline crystals enclosed by phenocrysts of orthoclase and quartz in a matrix of quartz, tourmaline, alkali feldspar, brown mica, and cassiterite.