Peperine

Peperino is an Italian name applied to a brown or grey volcanic tuff, containing fragments of basalt and limestone, with disseminated crystals of augite, mica,magnetite, leucite, and other similar minerals. The typical peperino occurs in the Alban Hills and in Soriano nel Cimino, near Rome, and was used by the ancients, under the name of lapis albanus, as a building stone and for the basins of fountains. The name originally referred to the dark-colored inclusions, suggestive of pepper-corns. In English the word has sometimes been written "peperine".

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Peperine from Alban Hills, Italy. The dark "spot" are "fiamme" (glassy fragments).

Peperine from Alban Hills, Italy. The dark "spot" are "fiamme" (glassy fragments).

Panoramic view of "peperine" ignimbrite thin section. Image by Andy Tindle (Virtual Microscope). PPL image, field of view = 2.5cm.

Panoramic view of "peperine" ignimbrite thin section. Image by Andy Tindle (Virtual Microscope). XPL image, field of view = 2.5cm.

Bibliography

• Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Le Maitre, R. W., Streckeisen, A., Zanettin, B., Le Bas, M. J., Bonin, B., Bateman, P., & Lameyre, J. (2002). Igneous rocks. A classification and glossary of terms, 2. Cambridge University Press.
• Middlemost, E. A. (1986). Magmas and magmatic rocks: an introduction to igneous petrology.
• 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.

Photo
Pyroxene, plagiolcase and biotite embedded in a eutaxitic groundmass. PPL image, 2x (Field of view = 7mm)	Pyroxene, plagiolcase and biotite embedded in a glassy eutaxitic groundmass. XPL image, 2x (Field of view = 7mm)	Pyroxene, plagiolcase and biotite embedded in a eutaxitic groundmass. PPL image, 2x (Field of view = 7mm)
Pyroxene, plagiolcase and biotite embedded in a glassy eutaxitic groundmass. XPL image, 2x (Field of view = 7mm)	Pyroxene, plagiolcase and biotite embedded in a eutaxitic groundmass. PPL image, 2x (Field of view = 7mm)	Pyroxene, plagiolcase and biotite embedded in a glassy eutaxitic groundmass. XPL image, 2x (Field of view = 7mm)
Pyroxene, plagiolcase and biotite embedded in a glassy eutaxitic groundmass. XPL image, 2x (Field of view = 7mm)	Pyroxene, plagiolcase and biotite embedded in a eutaxitic groundmass. PPL image, 2x (Field of view = 7mm)	Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)
Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)	Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)	Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)
Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)	Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)	Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)
Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)	Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)	Eutaxitic groundmass. PPL image, 10x (Field of view = 2mm)