Chrysocolla - (Cu,Al)2H2Si2O5(OH)4*nH2O

Chrysocolla is a mineral of secondary origin (formed as a decomposition product of copper minerals), commonly associated with other secondary copper minerals, it is typically found as glassy botryoidal or rounded masses or bubbly crusts, and as jackstraw mats of tiny acicular crystals or tufts of fibrous crystals. The name was first used by Theophrastus in 315 B.C. and comes from the Greek chrysos, meaning "gold," and kolla, meaning "glue," in allusion to the name of the material used to solder gold. It occurs typically in the upper parts of copper ore veins where the copper minerals have been altered by water containing dissolved silica. Crane et al. (1998) proposed that chrysocolla is formed by the reaction of copper hydroxy carbonate with siliceous acid according to the reaction:

Cu3(CO3)2(OH)2 (azurite) + 3H4SiO4 (siliceous acid) = 3CuSiO2*H2O (chrysocolla) + 4H2O + 2CO2

Optical properties:
• Form: Most often found as cryptocrystalline to amorphous botryoidal aggregates and crusts.
• Color: Blue, blue-green.
• Relief: Moderate.
• Interference colors: High.



Bibliography



• Bucher, K., & Grapes, R. (2011). Petrogenesis of metamorphic rocks. Springer Science & Business Media.
• Fossen, H. (2016). Structural geology. Cambridge University Press.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Passchier, Cees W., Trouw, Rudolph A. J: Microtectonics (2005).
• Philpotts, A., & Ague, J. (2009). Principles of igneous and metamorphic petrology. Cambridge University Press.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.
• Vernon, R. H. (2018). A practical guide to rock microstructure. Cambridge university press.


Photo
crisocolla(1).jpg

Fibrous aggregates of chrysocolla (light green-blue) and green malachite crystals. Copper ore, Arizona (USA). PPL image, 2x (Field of view = 7mm)		 crisocolla(2).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)		 crisocolla(5).jpg

Fibrous aggregates of chrysocolla (light green-blue) and green malachite crystals. Copper ore, Arizona (USA). PPL image, 2x (Field of view = 7mm)
crisocolla(6).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)		 crisocolla(8).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)		 crisocolla(10).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)
crisocolla(13).jpg

Fibrous aggregates of chrysocolla (light green-blue) and green malachite crystals. Copper ore, Arizona (USA). PPL image, 2x (Field of view = 7mm)		 crisocolla(14).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)		 crisocolla(17).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)
crisocolla(18).jpg

Fibrous aggregates of chrysocolla (light green-blue) and green malachite crystals. Copper ore, Arizona (USA). PPL image, 2x (Field of view = 7mm)		 crisocolla(19).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)		 crisocolla(20).jpg

Fibrous aggregates of chrysocolla (light green-blue) and green malachite crystals. Copper ore, Arizona (USA). PPL image, 2x (Field of view = 7mm)
crisocolla(21).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)		 crisocolla(22).jpg

Fibrous aggregates of chrysocolla (light green-blue) and green malachite crystals. Copper ore, Arizona (USA). PPL image, 2x (Field of view = 7mm)		 crisocolla(23).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 2x (Field of view = 7mm)
crisocolla(28).jpg

Fibrous aggregates of chrysocolla (light green-blue) and green malachite crystals. Copper ore, Arizona (USA). PPL image, 10x (Field of view = 2mm)		 crisocolla(29).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(30).jpg

Fibrous aggregates of chrysocolla (light green-blue) and green malachite crystals. Copper ore, Arizona (USA). PPL image, 10x (Field of view = 2mm)
crisocolla(31).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(29).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite crystals. Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(26).jpg

Fibrous aggregates of chrysocolla (high interference colors). Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)
crisocolla(27).jpg

Fibrous aggregates of chrysocolla (high interference colors). Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(32).jpg

Fibrous aggregates of chrysocolla (high interference colors). Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(33).jpg

Fibrous aggregates of chrysocolla (high interference colors). Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)
crisocolla(36).jpg

Fibrous aggregates of chrysocolla (high interference colors). Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(37).jpg

Fibrous aggregates of chrysocolla (high interference colors). Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(40).jpg

Fibrous aggregates of chrysocolla (high interference colors). Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)
crisocolla(41).jpg

Fibrous aggregates of chrysocolla (high interference colors). Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(44).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite. Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)		 crisocolla(45).jpg

Fibrous aggregates of chrysocolla (high interference colors) and green malachite. Copper ore, Arizona (USA). XPL image, 10x (Field of view = 2mm)