Difference between revisions of "Posnjakite"

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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).
 
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).
[[File:Posnjakite Raman RRUFF R110172.png|thumb|Raman spectrum of Posnjakite; Credit: [[https://rruff.info/posnjakite/display=default/ RRUFF]]]
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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 ==
  

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