Fundamental Minerals

Sialic Minerals

• Feldspar
Feldspar
Sanidine
Plagioclase

• Feldspathoid
Feldspathoids
Haüyne
Kalsilite
Leucite
Nepheline


• Quartz

Femic Minerals

• Amphiboles
• Aenigmatite
• Biotite
• Sagenitic biotite
• Melilite
• Olivine
• Pyroxene
Structure
Clinopyroxene
Orthopyroxene

Accessory Minerals

• Andradite
• Apatite
• Cordierite
• Chromite
• Magnetite
• Ilmenite
• Titanite

Very Rare Minerals

• Gregorite
• Nyerereite
• Priderite

Secondary Minerals

• Calcite
• Chlorite
• Hematite
• Epidote
• Orpiment
• Phillipsite
• Pinite

Texture

• Amygdales
• Embayed
• Eutaxitic
• Felsic
• Glomerophyric
• Hyalopilitic
• Hypocrystalline
• Holohyaline
• Intergranular
• Intersertal
• Magmatic flow
• Opacitic rim
• Ophitic
• Poikilitic
• Pilotassitic
• Porphyritic
• Sieve
• Skeletal
• Spinifex
• Trachytic
• Vitrophyric
• Zoning
• Xenocryst
• Xenolith

Alteration Products

• Bowlingite
• Iddingsite
• Pseudomorph
• Saussurite
• Sericite
• Uralite

Glass and related Texture

• Volcanic glass
• Fiamme
• Perlite
• Palagonite
• Spherulites
• Shards

Volcanic Rocks

• Aillikite
• Alnöite
• Andesite
• Ankaramite
• Basalt
• Benmoreite
• Bergalite
• Comendite
• Coppaelite
• Dacite
• Dacite (devitrified)
• Garnet dacite
• Foidite
• Foidite (nepheline)
• Haüynophyre
• Hyaloclastite
• Horneblende Andesite
• Ignimbrite
• Ignimbrite (pantelleritic)
• Kaiserstuhl
Kaiserstuhl
Bergalite
Carbonatitic lapillistone
Diatreme breccia
Limburgite
Olivine nephelinite
Tephrite
Sövite
Wollastonite phonolite

• Kersantite
• Kimberlites
Kimberlites
Varty lake (Canada)
Sturgeon lake (Canada)
Monastery (S.Africa)
Udachnaya (Russia)
• Komatiites
Komatiites
Alexo (Canada)
Belingwe (Zimbawe)

• Lamprophyres
Lamprophyres
Aillikite
Alnöite
Bergalite
Kersantite
Monchiquite
Sannaite
Spessartite
Vosegite

• Lapillistone
• Latite
• Leucitite
• Limburgite
• Madupite (lamproite)
• Mafurite
• Monchiquite
• Natrocarbonatite
• Obsidian
• Oldoinyo Lengai
Ol Doinyo Lengai
Natrocarbonatite lava

• Peperine
• Pyroclastic flow
• Pitchstone
• Pillow lava
• Pumice
• Rhyolite
• Sannaite
• Scoria (basaltic)
• Scoria (phonolitic)
• Spessartite
• Tephrite
• Tephritic leucitite
• Tephritic phonolite
• Trachybasalt
• Trachyte
• Trachyte (foid-bearing)
• Venanzite
• Vitrophyre
• Vosegite

Pantelleritic ignimbrite

Pantellerite is a peralkaline rhyolite. It has a higher iron and lower aluminium composition than comendite. It is named after Pantelleria, a volcanic island in the Strait of Sicily and the type location for this rock. On Pantelleria the rock is usually found as a vitrophyre containing phenocrysts of anorthoclase or sanidine. Quartz is found only in the most strongly peralkaline rocks. Mafic minerals may include aegirine, fayalite, aenigmatite, ilmenite, and sodic amphibole (often arfvedsonite or ferrorichterite).

Pantellerite melts, such as those from the Island of Pantelleria, Italy, are characterized by high alkali and halogen contents compared to metaluminous magmas of equivalent silica content (or "normal rhyolites"). These peculiarities in geochemistry affect the rheological properties of peralkaline magmas, resulting in viscosities that are several orders of magnitude lower than those of "normal” rhyolites".

The rheology of peralkaline magmas affects profoundly their vesiculation, outgassing, flow and eruption. Peralkaline volcanic systems commonly exhibit substantial differences in the physical nature of their eruptive products with respect to metaluminous rhyolites. In contrast with calcalkaline centres, which produce widespread plinian deposits and ignimbrites, the dynamics of peralkaline rhyolite volcanic systems are more varied and complex, and not yet fully understood. Peralkaline volcanic centres show a close association between fall units, ignimbrites, deposits originating from lava fountains and lava domes and flows, documenting a continuous transition from explosive to less explosive styles of eruption. These kinds of associations are unique to pantellerites.

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

Sanidine, aegirine and aenigmatite (balck-red) in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine, aegirine and aenigmatite (balck-red) in a pantellerite from Pantelleria (Italy). XPL image, 2x (Field of view = 7mm)	Sanidine, aegirine and aenigmatite (balck-red) in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Sanidine in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and aegirine in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and aenigmatite (balck-red) in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Flattened pumice fragment in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and aegirine in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and aenigmatite (balck-red) in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Flattened pumice fragment, aegirine and aenigmatite (balck-red) in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Pumice fragments in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Sanidine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)
Aenigmatite (balck-red) and aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Sanidine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)
Sanidine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)
Sanidine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aenigmatite (balck-red) and aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)
Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aenigmatite (balck-red) embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)
Flattened, deformed pumice fragment in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Flattened, deformed pumice fragment in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Flattened, deformed pumice fragment in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Sanidine, aegirine and aenigmatite (black-red) in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Flattened, deformed pumice fragment in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Flattened, deformed pumice fragments in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Aegirine and sanidine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Xenolith embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine, Pumice fragments, Aegirine and aenigmatite embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Sanidine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and Aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and aenigmatite embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Sanidine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and Aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and aenigmatite embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Sanidine, pumice fragment and aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Sanidine and small xenolith embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)	Aegirine and aenigmatite embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 2x (Field of view = 7mm)
Aegirine embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aegirine and aenigmatite embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)	Aenigmatite embedded in a eutaxitic groundmass in a pantellerite from Pantelleria (Italy). PPL image, 10x (Field of view = 2mm)