Topaz

Topaz
Topaz
	Topaz crystal on white matrix
General
Category	Nesosilicate minerals
Formula; (repeating unit)	Al2SiO4(F,OH)2
IMA symbol	Tpz
Strunz classification	9.AF.35
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) ; H-M symbol: (2/m 2/m 2/m)
Space group	Pbnm
Unit cell	a = 4.65 Å, b = 8.8 Å, ; c = 8.4 Å; Z = 4
Identification
Color	Colorless (if there are no impurities), white, blue, brown, orange, gray, yellow, yellowish brown, green, pink, reddish pink or even red
Crystal habit	Prismatic crystal
Twinning	Rarely on [111]
Cleavage	[001] Perfect
Fracture	Subconchoidal to uneven
Mohs scale hardness	8 (defining mineral)
Luster	Vitreous
Streak	White
Diaphaneity	Transparent
Specific gravity	3.49–3.57
Optical properties	Biaxial (+)
Refractive index	nα = 1.606–1.629; nβ = 1.609–1.631; nγ = 1.616–1.638
Birefringence	δ = 0.010
Pleochroism	Weak in thick sections X = yellow; Y = yellow, violet, reddish; Z = violet, bluish, yellow, pink
Ultraviolet fluorescence	Short UV=golden yellow; Long UV=cream
References

Topaz is a silicate mineral made of aluminum and fluorine with the chemical formula Al₂Si O₄(F, OH)₂. It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden brown to yellow-orange.^[7] Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple.^[8]

Topaz is a nesosilicate mineral, and more specifically, an aluminosilicate mineral.^[9] It is one of the hardest naturally occurring minerals and has a relatively low index of refraction. It has the orthorhombic crystal system and a dipyramidial crystal class.^[10]

It occurs in many places in the world. Some of the most popular places where topaz is sourced are Brazil and Russia.^[7] Topaz is often mined in open pit or alluvial settings.^[11]

^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
^ Nesse, William D. (2000). Introduction to mineralogy. New York: Oxford University Press. p. 313. ISBN 9780195106916.
^ Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20 ed.). Wiley. ISBN 0-471-80580-7.
^ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (1995). "Topaz" (PDF). Handbook of Mineralogy. Vol. II (Silica, Silicates). Chantilly, VA, US: Mineralogical Society of America. ISBN 978-0-9622097-1-0. Retrieved December 5, 2011.
^ Topaz. Mindat.org. Retrieved on 2011-10-29.
^ Topaz. Webmineral.com. Retrieved on 2011-10-29.
^ ^a ^b Menzies, Michael A. (2023-12-08). "Connoisseur's Choice: Topaz from Granite Pegmatites: Limoeiro Mine, Virgem da Lapa, Araçuaí Pegmatite District, Minas Gerais, Brazil". Rocks & Minerals. 99 (1): 36–55. doi:10.1080/00357529.2023.2253100. ISSN 0035-7529. S2CID 266145193.
^ "Topaz Value, Price, and Jewelry Information". International Gem Society. Retrieved 2021-11-16.
^ Tennakoon, Sumudu; Peng, Ye; Mookherjee, Mainak; Speziale, Sergio; Manthilake, Geeth; Besara, Tiglet; Andreu, Luis; Rivera, Fernando (2018-01-22). "Single crystal elasticity of natural topaz at high-temperatures". Scientific Reports. 8 (1): 1372. Bibcode:2018NatSR...8.1372T. doi:10.1038/s41598-017-17856-3. ISSN 2045-2322. PMC 5778148. PMID 29358663.
^ Handbook of mineralogy. 2,2: Silica, Silicates: Pt. 2. Tucson, Ariz: Mineral Data Publ. 1995. ISBN 978-0-9622097-1-0.
^ "Topaz Mining: Balancing Resource Extraction and Sustainability". www.brilliyond.com. Retrieved 2024-03-20.

[1] Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.

[2] Nesse, William D. (2000). Introduction to mineralogy. New York: Oxford University Press. p. 313. ISBN 9780195106916.

[3] Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20 ed.). Wiley. ISBN 0-471-80580-7.

[Handbook-4] Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (1995). "Topaz" (PDF). Handbook of Mineralogy. Vol. II (Silica, Silicates). Chantilly, VA, US: Mineralogical Society of America. ISBN 978-0-9622097-1-0. Retrieved December 5, 2011.

[Mindat-5] Topaz. Mindat.org. Retrieved on 2011-10-29.

[Webmineral-6] Topaz. Webmineral.com. Retrieved on 2011-10-29.

[:0-7] Menzies, Michael A. (2023-12-08). "Connoisseur's Choice: Topaz from Granite Pegmatites: Limoeiro Mine, Virgem da Lapa, Araçuaí Pegmatite District, Minas Gerais, Brazil". Rocks & Minerals. 99 (1): 36–55. doi:10.1080/00357529.2023.2253100. ISSN 0035-7529. S2CID 266145193.

[8] "Topaz Value, Price, and Jewelry Information". International Gem Society. Retrieved 2021-11-16.

[9] Tennakoon, Sumudu; Peng, Ye; Mookherjee, Mainak; Speziale, Sergio; Manthilake, Geeth; Besara, Tiglet; Andreu, Luis; Rivera, Fernando (2018-01-22). "Single crystal elasticity of natural topaz at high-temperatures". Scientific Reports. 8 (1): 1372. Bibcode:2018NatSR...8.1372T. doi:10.1038/s41598-017-17856-3. ISSN 2045-2322. PMC 5778148. PMID 29358663.

[10] Handbook of mineralogy. 2,2: Silica, Silicates: Pt. 2. Tucson, Ariz: Mineral Data Publ. 1995. ISBN 978-0-9622097-1-0.

[:6-11] "Topaz Mining: Balancing Resource Extraction and Sustainability". www.brilliyond.com. Retrieved 2024-03-20.

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