Difference between revisions of "Posnjakite"

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[[File:Posnjakite-113800.jpg|thumb|Posnjakite specimen<br>Image credit: Leon Hupperichs]]
 
== Description ==
 
== Description ==
  
A blue-green mineral that has been occasionally found as a pigment. Posnjakite occurs naturally in deposits of [http://cameo.mfa.org/materials/fullrecord.asp?name=malachite malachite]. Recipes for the synthetic preparation of posnjakite are given in a late 18th century paint manual (Naumova and Pisareva, 1994). Posnjakite has also been found as a [http://cameo.mfa.org/materials/fullrecord.asp?name=bronze bronze] corrosion product where it is thought to be a precursor to [http://cameo.mfa.org/materials/fullrecord.asp?name=brochantite brochantite] formation (Selwyn, et al., 1996).
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A blue-green mineral that has been occasionally found as a pigment. Posnjakite occurs naturally in deposits of [[malachite|malachite]]. Recipes for the synthetic preparation of posnjakite are given in a late 18th century paint manual (Naumova and Pisareva, 1994). Posnjakite has also been found as a [[bronze|bronze]] corrosion product where it is thought to be a precursor to [[brochantite|brochantite]] formation (Selwyn, et al., 1996).
 
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[[File:Posnjakite Raman RRUFF R110172.png|thumb|Raman spectrum of Posnjakite; Credit: [https://rruff.info/posnjakite/display=default/ RRUFF]]]
 
== Synonyms and Related Terms ==
 
== Synonyms and Related Terms ==
  
 
Posnnakit (Deut.)
 
Posnnakit (Deut.)
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==Physical and Chemical Properties==
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* Composition = Cu<sub>4</sub>SO<sub>4</sub>(OH)<sub>6</sub>-H2O
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* Description = green blue to dark blue scaly crystals
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* Luster = vitreous
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* Hardness = 2 - 3
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* Density = 3.4
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==Resources and Citations==
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* M.Naumova, S.Pisareva,"A Note on the Use of Blue and Green Copper Compounds in Paintings" ''Studies in Conservation'' 39:277-283, 1994.
  
{| class="wikitable"
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* L.Selwyn, N.Binnie, J.Poitras, M.Laver, D.Downham, "Outdoor Bronze Statues: Analysis of Metal and Surface Samples" ''Studies in Conservation'' 41:205-228, 1996.
|-
 
! scope="row"| Composition
 
| Cu4SO4(OH)5-H2O
 
|-
 
! scope="row"| Mohs Hardness
 
| 2 - 3
 
|}
 
  
== Additional Information ==
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* Wikipedia: [https://en.wikipedia.org/wiki/Posnjakite] accessed Dec 2022
  
° M.Naumova, S.Pisareva,"A Note on the Use of Blue and Green Copper Compounds in Paintings" ''Studies in Conservation'' 39:277-283, 1994. ° L.Selwyn, N.Binnie, J.Poitras, M.Laver, D.Downham, "Outdoor Bronze Statues: Analysis of Metal and Surface Samples" ''Studies in Conservation'' 41:205-228, 1996.
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* Webmineral: [http://www.webmineral.com/data/Posnjakite.shtml#.Y5D5A9jMJwQ Posnjakaite]
  
 
[[Category:Materials database]]
 
[[Category:Materials database]]

Latest revision as of 15:47, 7 December 2022

Posnjakite specimen
Image credit: Leon Hupperichs

Description

A blue-green mineral that has been occasionally found as a pigment. Posnjakite occurs naturally in deposits of Malachite. Recipes for the synthetic preparation of posnjakite are given in a late 18th century paint manual (Naumova and Pisareva, 1994). Posnjakite has also been found as a Bronze corrosion product where it is thought to be a precursor to Brochantite formation (Selwyn, et al., 1996).

Raman spectrum of Posnjakite; Credit: RRUFF

Synonyms and Related Terms

Posnnakit (Deut.)

Physical and Chemical Properties

  • Composition = Cu4SO4(OH)6-H2O
  • Description = green blue to dark blue scaly crystals
  • Luster = vitreous
  • Hardness = 2 - 3
  • Density = 3.4

Resources and Citations

  • M.Naumova, S.Pisareva,"A Note on the Use of Blue and Green Copper Compounds in Paintings" Studies in Conservation 39:277-283, 1994.
  • L.Selwyn, N.Binnie, J.Poitras, M.Laver, D.Downham, "Outdoor Bronze Statues: Analysis of Metal and Surface Samples" Studies in Conservation 41:205-228, 1996.
  • Wikipedia: [1] accessed Dec 2022