Hale, D. R. (1948). "The Laboratory Growing of Quartz". Science. 107 (2781): 393–394. Bibcode: 1948Sci...107..393H. doi: 10.1126/science.107.2781.393. PMID 17783928. The ancient Greeks believed amethyst gems could prevent intoxication, [23] while medieval European soldiers wore amethyst amulets as protection in battle in the belief that amethysts heal people and keep them cool-headed. [24] Beads of amethyst were found in Anglo-Saxon graves in England. [25] Anglican bishops wear an episcopal ring often set with an amethyst, an allusion to the description of the Apostles as "not drunk" at Pentecost in Acts 2:15. [26] Rutile, a titanium oxide (TiO2) forms in the tetragonal crystal system as prismatic needle-like acicular crystals. One of the most common inclusions in quartz. With colours ranging from yellow to brownish-yellow, which are the more common colours, and deep red to brownish-red, which are less common and therefore more desirable. Rutile stars are very sought after.

Anderson, Robert S.; Anderson, Suzanne P. (2010). Geomorphology: The Mechanics and Chemistry of Landscapes. Cambridge University Press. p.187. ISBN 978-1-139-78870-0.Nesse, William D. (2000). Introduction to mineralogy. New York: Oxford University Press. p.205. ISBN 9780195106916. Synthetic amethyst is made to imitate the best quality amethyst. Its chemical and physical properties are the same as those of natural amethyst, and it cannot be differentiated with absolute certainty without advanced gemmological testing (which is often cost-prohibitive). One test based on "Brazil law twinning" (a form of quartz twinning where right- and left-hand quartz structures are combined in a single crystal [27]) can be used to identify most synthetic amethyst rather easily. Synthesizing twinned amethyst is possible, but this type is not available in large quantities in the market. [7] The largest documented single crystal of quartz was found near Itapore, Goiaz, Brazil; it measured approximately 6.1m × 1.5m × 1.5m and weighed 39,916 kilograms. [81] Mining [ edit ]

a b Fernando S. Lameiras; Eduardo H. M. Nunes; Wander L. Vasconcelos (2009). "Infrared and Chemical Characterization of Natural Amethysts and Prasiolites Colored by Irradiation". Materials Research. 12 (3): 315–320. doi: 10.1590/S1516-14392009000300011.

Amethyst Jewelry and Gemstones Information - International Gem Society IGS". gemsociety.org . Retrieved October 3, 2014. Driscoll, Killian. 2010. Understanding quartz technology in early prehistoric Ireland". Archived from the original on 25 June 2017 . Retrieved 19 July 2017. Blue Quartz is a stone that can easily adjust to whoever holds it. However, its healing properties resonate more with specific zodiac signs. Pyrite is one of the more common inclusions in quartz. It’s an iron sulphide (FeS 2) and occurs in an opaque yellow to brownish-yellow coloured mineral with a metallic lustre. Forming in the cubic crystal system it usually forms a cubes and commonly twins. Pyrite less commonly forms as octahedrons, which can be seen pictured below.

Tarr, W. A (1929). "Doubly terminated quartz crystals occurring in gypsum". American Mineralogist. 14 (1): 19–25 . Retrieved 7 April 2021. Blue Quartz". Mindat.org. Archived from the original on 24 February 2017 . Retrieved 24 February 2017. Quartz | Definition of quartz by Lexico". Archived from the original on 1 December 2017 . Retrieved 26 November 2017.Some of its most desired benefits revolve around the immune system. A common belief is that the stone’s peaceful energy supports your immune health so that your body can naturally fight off diseases. Many also say that the peaceful aura the crystal creates makes your body more capable of keeping you healthy. Prasiolite, an olive colored material, is produced by heat treatment; [70] natural prasiolite has also been observed in Lower Silesia in Poland. [71] Although citrine occurs naturally, the majority is the result of heat-treating amethyst or smoky quartz. [70] Carnelian has been heat-treated to deepen its color since prehistoric times. [72] Quartz and its colored varieties". California Institute of Technology. Archived from the original on 19 July 2011. Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (eds.). "Quartz" (PDF). Handbook of Mineralogy. Vol.III (Halides, Hydroxides, Oxides). Chantilly, VA: Mineralogical Society of America. ISBN 0962209724. Archived (PDF) from the original on 1 April 2010 . Retrieved 21 October 2009. Meanwhile, Pisces are more likely to internalize their emotions. While they seem calm on the outside, there’s always a battle brewing underneath.

Fridrichová, Jana; Bačík, Peter; Illášová, Ľudmila; Kozáková, Petra; Škoda, Radek; Pulišová, Zuzana; Fiala, Anton (July 2016). "Raman and optical spectroscopic investigation of gem-quality smoky quartz crystals". Vibrational Spectroscopy. 85: 71–78. doi: 10.1016/j.vibspec.2016.03.028. Marcell N. Smith (1913), Diamonds, Pearls and Precious Stones Griffith Stillings Press, Boston, Mass., p. 74 Green quartz is sometimes incorrectly called green amethyst; this is a misnomer and not an appropriate name for the material, as the proper terminology is prasiolite. [9] Other names for green quartz are vermarine or lime citrine. Amethyst is relatively common in the Canadian provinces of Ontario and Nova Scotia. The largest amethyst mine in North America is located in Thunder Bay, Ontario. [14]Collectors look for depth of color, possibly with red flashes if cut conventionally. [39] As amethyst is readily available in large structures, the value of the gem is not primarily defined by carat weight. This is different from most gemstones, since the carat weight typically exponentially increases the value of the stone. The biggest factor in the value of amethyst is the color displayed. [40] Byrappa, K. and Yoshimura, Masahiro (2001) Handbook of Hydrothermal Technology. Norwich, New York: Noyes Publications. ISBN 008094681X. Chapter 2: History of Hydrothermal Technology. Tyndall scattering is one of the rarest phenomena in gemology, but it is relatively common in Madagascar rose quartz. Tyndall scattering is where light is dispersed by fine particles and produces a blue color. This is the same as what happens when sunlight hits dust particles in the air and why the is sky blue. In rose quartz, you see both pink and blue in the same tone. Relatively new on the market is ametrine, with zones of both purple and yellow. The colors only reach a medium level of saturation and are never very dark. Cutting the material so both color show is sometimes a challenge for the lapidary. However, a well cut, bi-colored gem is a real delight. Ametrine is only found in Bolivia. Smokey Quartz Quartz is one of the most common stones in the crystal kingdom. However, Blue Quartz is a rarity that many practitioners jump at the opportunity to own!