Venanzite

Venanzite: Melanocratic variety of leucite olivine melilitite largely composed of melilite, leucite, kalsilite and olivine. Rosenbusch (1899) called this rock euktolite unaware that it had already been named venanzite. A kamafugitic rock and now regarded as a kalsilite-phlogopite-olivine-leucite melilitite.

For more information about the San Venanzo volcanic complex, see page: "San Venanzo"

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Contact between coarse-grained Pegmatitic Venanzinte and venanzite lava at Pian di Celle.



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Coarse-grained Pegmatitic Venanzinte at Pian di Celle. The honey-orange crystals are Phlogopite.





Bibliography



• Stoppa, F., & Sforna, S. (1995). Geological map of the San Venanzo volcano (Central Italy): explanatory notes. Acta Vulcanologica, 7(1), 85-91.
• Stoppa, F. (1996). The San Venanzo maar and tuff ring, Umbria, Italy: eruptive behaviour of a carbonatite-melilitite volcano. Bulletin of Volcanology, 57(7), 563-577.
• Stoppa, F., & Cundari, A. (1998). Origin and multiple crystallization of the kamafugite-carbonatite association: The San Venanzo-Pian di Celle occurrence (Umbria, Italy). Mineralogical Magazine, 62(2), 273-289.
• Peccerillo.A (2005): Plio-Quaternary Volcanism in Italy.


Photo
vvenanzitee(3).jpg

Olivine crystals embedded in a groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 2x (Field of view = 7mm)
vvenanzitee(4).jpg

Olivine crystals embedded in a groundmass made by melilite and olivine. XPL image, 2x (Field of view = 7mm)
vvenanzitee(5).jpg

Olivine crystals embedded in a groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 2x (Field of view = 7mm)
vvenanzitee(6).jpg

Olivine crystals embedded in a groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 2x (Field of view = 7mm)
vvenanzitee(10).jpg

Olivine crystal embedded in a groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 10x (Field of view = 2mm)
vvenanzitee(11).jpg

Olivine crystal embedded in a groundmass made by melilite (the small crystals with blue interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(7).jpg

Olivine crystals embedded in a groundmass made by melilite and olivine. XPL image, 2x (Field of view = 7mm)
vvenanzitee(16).jpg

Olivine crystals embedded in a groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 2x (Field of view = 7mm)
vvenanzitee(17).jpg

Olivine crystal embedded in a groundmass made by melilite (the small crystals with blue interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(32).jpg

Groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 10x (Field of view = 2mm)
vvenanzitee(33).jpg

Groundmass made by melilite (the small crystals with blue interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(34).jpg

Groundmass made by melilite (the small crystals with blue interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(8).jpg

Groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 10x (Field of view = 2mm)
vvenanzitee(9).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(12).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(13).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(14).jpg

Groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 10x (Field of view = 2mm)
vvenanzitee(15).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(18).jpg

Olivine crystal embedded in a groundmass made by melilite (the small crystals with blue interfence colors) and olivine. XPL image, 2x (Field of view = 7mm)
vvenanzitee(19).jpg

Olivine crystal embedded in a groundmass made by melilite (the small crystals with blue interfence colors) and olivine. XPL image, 2x (Field of view = 7mm)
vvenanzitee(20).jpg

Groundmass made by melilite (the small rectangular crystals) and olivine. PPL image, 10x (Field of view = 2mm)
vvenanzitee(21).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(22).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(23).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(29).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(30).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(31).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(35).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)
vvenanzitee(36).jpg

Groundmass made by melilite (the small crystals with blue-gray interfence colors) and olivine. XPL image, 10x (Field of view = 2mm)