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: | + | [[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 14:47, 7 December 2022
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
- Webmineral: Posnjakaite