Connellite

Connellite
Image credit: Rob Lavinsky

Description

Raman spectrum of Connellite, Credit: RRUFF

A rare blue green copper corrosion product that forms delicate acicular crystals. Connellite was found as a mineral in Cornwall in 1802 by Philip Rashleigh and was examined chemically by Arthur Connell in 1847. It has also been found on prehistoric bronzes.

Physical and Chemical Properties

• Composition = Cu₁₉Cl₄SO₄)(OH)₃₂ 3H2O
• Blue green to light blue fibrous to acicular needles
• Lust = vitreous to glass
• Streak = light blue green
• Hardness = 3
• Density = 3.4

Resources and Citations

• H. Otto 'Das Vorkommen von Conellit in Patinaschichten", Die Naturwissenschaften 50(1):16-17, 1963.

• Walter A. Franke, Magda Mircea, "Plutarch's Report on the Blue Patina of Bronze Statues at Delphi: A Scientific Explanation" JAIC 44(2):103, 2005.

• Wikipedia: http://en.wikipedia.org/wiki/Connellite (accessed Nov. 30, 2005)

• Webmineral: Connellite