View source for Chrysocolla

{{Short description|Phyllosilicate mineral}}
{{Infobox mineral
| name        = Chrysocolla
| category    = [[Phyllosilicate]] [[minerals]]
| boxwidth    = 
| boxbgcolor  = #36cacb 
| image       = Chrysocolla-230109.jpg
| caption     = Chrysocolla specimen from [[Ray mine]], in the [[Scott Mountain (Arizona)|Scott&nbsp;Mountain]] area of Mineral Creek District, [[Pinal County, Arizona]], US 
| formula     = {{chem2|Cu_{2 – ''x''}Al_{''x''}(H2Si2O5)(OH)4*''n''H2O}} (''x''&nbsp;<&nbsp;1)<ref name=Mindat/>
| IMAsymbol   = Ccl<ref>{{cite journal |last=Warr|first=L. N. |year=2021 |title=IMA–CNMNC approved mineral symbols |journal=[[Mineralogical Magazine]] |volume=85 |issue=3 |pages=291–320 |doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free}}</ref>
| strunz      = 9.ED.20
| symmetry    = 
| unit cell   = a = 5.7&nbsp;Å, b = 8.9&nbsp;Å, <br/>c = 6.7&nbsp;Å; Z&nbsp;=&nbsp;1
| color       = Blue, [[cyan]] ([[blue-green]]), green, dark blue to black, brown, rarely yellow
| habit       = Massive, nodular, [[botryoidal]] 
| system      = [[orthorhombic crystal system|Orthorhombic]] <br/>Unknown space group
| twinning    = 
| cleavage    = none
| fracture    = Irregular/uneven, sub-[[conchoidal fracture|conchoidal]]
| tenacity    = [[brittleness|Brittle]] to [[sectility|sectile]]
| mohs        = 2.5–3.5 (7 for chrysocolla chalcedony, high-silica content)
| luster      = Vitreous to dull
| refractive  = n<sub>α</sub> = 1.575–1.585 n<sub>β</sub> = 1.597 n<sub>γ</sub> = 1.598–1.635
| opticalprop = Biaxial (−)
| birefringence = δ = 0.023–0.050
| pleochroism = 
| streak      = White to a blue-green color
| gravity     = 1.9–2.4
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| diaphaneity = Translucent to opaque
| other       = 
| references  = <ref>{{cite web |url=https://mineralienatlas.de/lexikon/index.php/MineralData?lang=en&mineral=Chrysocolla |title=Chrysocolla |website=Mineralienatlas – Fossilienatlas}}</ref><ref name=HBM>{{cite web |url=https://rruff.info/doclib/hom/chrysocolla.pdf |title=Chrysocolla |website=Handbook of Mineralogy}}</ref><ref name=Mindat>{{Mindat |id=1040 |name=Chrysocolla}}</ref><ref name=Webmin>{{WebMineral |url=https://webmineral.com/data/Chrysocolla.shtml |title=Chrysocolla Mineral Data |first=Dave|last=Barthelmy}}</ref>
}}

'''Chrysocolla''' ({{IPAc-en|ˌ|k|r|ɪ|s|ə|ˈ|k|ɒ|l|ə}} {{respell|KRIS|ə|KOL|ə}}) is a [[hydrate|hydrous]] [[copper]] [[phyllosilicate]] [[mineral]] and [[mineraloid]] with the [[chemical formula|formula]] {{chem|Cu|2 – ''x''|Al|''x''|(H|2|Si|2|O|5|)(OH)|4|⋅''n''H|2|O}} (''x''&nbsp;<&nbsp;1)<ref name=Mindat/> or {{chem|(Cu|, Al)|2|H|2|Si|2|O|5|(OH)|4|⋅''n''H|2|O)}}.<ref name=HBM/>

The structure of the mineral has been questioned, as a 2006 spectrographic study suggest material identified as chrysocolla may be a mixture of the copper hydroxide [[spertiniite]] and [[chalcedony]].<ref name=farges2006/>

Chrysocolla typically forms amorphously.<ref>{{Cite web |last=Chen |first=Chermaine |date=2021-09-02 |title=Chrysocolla Stone: Meaning, Uses & Other Facts about this Blue Green Crystal |url=https://thegemlibrary.com/chrysocolla-stone/ |access-date=2024-07-25 |website=The Gem Library |language=en-GB}}</ref>

==History==
The name ''chrysocolla'' comes from the [[Ancient Greek]] {{wikt-lang|grc|χρυσός}} (''{{grc-transl|χρυσός}}'') and {{wikt-lang|grc|κολλα}} (''{{grc-transl|κολλα}}''), meaning "gold" and "glue" respectively,<ref>{{cite EB1911 |wstitle=Chrysocolla |volume=6 |page=320 |first=Leonard James|last=Spencer}}</ref> in allusion to the name of the material used to [[soldering|solder]] [[gold]]. The word was first used by [[Theophrastus]] in 315&nbsp;BC.

==Geology==
Chrysocolla has a [[cyan]] (blue-green) color and is a minor ore of copper, having a [[Mohs hardness|hardness]] of 2.5 to 7.0. It is of secondary origin and forms in the [[oxidation]] zones of copper [[ore]] bodies. Associated minerals are [[quartz]], [[limonite]], [[azurite]], [[malachite]], [[cuprite]], and other secondary copper minerals.  It is typically found as [[botryoidal]] or rounded masses and crusts, or vein fillings.

A 2006 study has produced evidence that chrysocolla may be a microscopic mixture of the copper hydroxide mineral [[spertiniite]], amorphous silica and water.<ref name=farges2006>[http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-12232.pdf François Farges, Karim Benzerara, Gordon E. Brown, Jr.; ''Chrysocolla Redefined as Spertiniite''; SLAC-PUB-12232; 13th International Conference On X-Ray Absorption Fine Structure (XAFS13); July 9-14, 2006; Stanford, California]</ref><ref name=Mindat/>

==Jewelry==
Due to being somewhat more common than [[turquoise]], its wide availability, and vivid, beautiful blue and blue-green colors, chrysocolla has been popular for use as a gemstone for carvings and ornamental use since antiquity. It is often used in [[silversmithing]] and [[goldsmithing]] in place of turquoise and is relatively easy to work and shape. Chrysocolla exhibits a wide range of [[Mohs hardness]] ranging from 2 through 7, which is dependent on the amount of silica incorporated into the stone when it is forming. Generally, dark navy blue chrysocolla is too soft to be used in jewelry, while cyan, green, and blue-green chrysocolla can have a hardness approaching 6, similar to turquoise. Chrysocolla chalcedony is a heavily silicified form of chrysocolla that forms in quartz deposits and can be very hard and approach a hardness of 7.<ref>{{cite web|url=https://geology.com/gemstones/gem-silica/|title=Gem Silica: The blue, most valuable variety of chalcedony|website=geology.com}}</ref><ref>{{cite web|url=http://www.minerals.net/gemstone/chrysocolla_gemstone.aspx|title=Chrysocolla: The gemstone chrysocolla information and pictures|website=www.minerals.net}}</ref><ref>{{cite web|url=https://www.gemsociety.org/article/chrysocolla-gemstone-information/|title=Chrysocolla Value, Price, and Jewelry Information - IGS}}</ref>

==Gallery==
<gallery widths="200px" heights="180px">
Chrysocolla-Tyrolite-Clinotyrolite-202106.jpg|Powder-blue chrysocolla as stalactitic growths and as a thin carpet in vugs inside a boulder of nearly solid [[tyrolite]], from the San Simon Mine, [[Iquique Province]], Chile (size: {{cvt|14.1|×|8.0|×|7.8|cm|in}})
Chrysocolla-201585.jpg|Banded white to blue green chrysocolla, from [[Bisbee, Arizona]] (size: {{cvt|12.2|×|5.5|×|5.2|cm|in}})
Chrysocolla-bolo.jpg|Chrysocolla and silver [[bolo tie]]. This chrysocolla specimen is from the [[Kennecott Utah Copper|Kennecot Copper Mine]] in [[Bingham Canyon]], [[West Valley City, Utah]].
Brochantite-Chrysocolla-k329b.jpg|[[Brochantite]] (emerald green) and chrysocolla, from the Rokana Mine, Zambian Copperbelt
</gallery>

==See also==
*[[Chrysocolla (gold-solder)]]

==References==
{{Commons category}}
{{Reflist|30em}}

{{Authority control}}
{{Phyllosilicates}}
{{Jewellery}}

[[Category:Copper ores]]
[[Category:Phyllosilicates]]
[[Category:Orthorhombic minerals]]
[[Category:Gemstones]]
[[Category:Blendes]]