Hypocrystalline Texture

Hypocrystalline is a textural term describing an igneous rock consisting of a mixture of glass and crystals where the ratio of crystals to glass is greater than 3:5.
Rocks containing a higher ratio of glass are described as hypohaline or holohyaline. Usually devitrified glass is treated as glass in the classification of hypohyaline rocks.

Bibliography



• Deer, W.A., Howie, R.A., Zussman, J. (1998) Rock-forming Minerals.
• Optical Mineralogy : The Nonopaque Minerals by Phillips / Griffen
• E. WM. Heinrich (1956): Microscopic Petrografy. Mcgraw-hill book company,inc
• Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.

Photo
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Plagioclase (with Sieve texture) in an Andesite with Hypocrystalline groundmass. XPL image , 2x (Field of view = 7mm)
ipocristallina2012(4).jpg

Plagioclase (with Sieve texture) in an Andesite with Hypocrystalline groundmass. PPL image , 2x (Field of view = 7mm)
ipocristallina2012(5).jpg

Plagioclase (with Sieve texture) in an Andesite with Hypocrystalline groundmass. PPL image , 2x (Field of view = 7mm)
ipocristallina2012(6).jpg

Plagioclase (with Sieve texture) in an Andesite with Hypocrystalline groundmass. PPL image , 2x (Field of view = 7mm)
ipocristallina2012(7).jpg

Plagioclase (with Sieve texture) in an Andesite with Hypocrystalline groundmass. XPL image , 2x (Field of view = 7mm)
ipocristallina2012(8).jpg

Plagioclase (with Sieve texture) in an Andesite with Hypocrystalline groundmass. PPL image , 2x (Field of view = 7mm)
ipocristallina2012(9).jpg

Plagioclase (with Sieve texture) in an Andesite with Hypocrystalline groundmass. XPL image , 2x (Field of view = 7mm)
ipocristallina2012(11).jpg

Plagioclase in an Andesite with Hypocrystalline groundmass. PPL image , 10x (Field of view = 2mm)
ipocristallina2012(10).jpg

Plagioclase (with Sieve texture) in an Andesite with Hypocrystalline groundmass. PPL image , 10x (Field of view = 2mm)