Taramellite- Ba₄(Fe³⁺,Ti)₄O₂[B₂Si₈O₂₇]Clx; x = 0 to 1

Taramellite, named after Torquato Taramelli, professor of geology, University of Pavia (Italy), is a mineral rich in barium and occurring in brownish red radially fibrous aggregates in metamorphic contact rocks; it was first described in the Candoglia marble quarries in Ivrea Verbano, Italy. Taramellite is associated with: calcite, diopside, actinolite, magnetite, pirite, calcopirite.

Optical Properties:
• Form: Crystals made up of fibers.
• Color: Reddish brown, Bronze purple, Brownish violet.
• pleochroism: Strong.
• Relief: Very High.
• Interference colors: Very High but masked by the color of the mineral.

The Candoglia marble

The quarries of Candoglia, Northern Italy, were firstly opened near the Candoglia village, but later their location moved up to higher levels. Now there are five recognisable extraction sites: Madre quarry (Cava Madre), active underground quarry at an elevation of 560 m a.s.l.; Carrettone quarry (Cava Carrettone), abandoned open pit quarry; Cornovo West quarry (Cava Cornovo Ovest), abandoned open pit quarry; Cornovo East quarry (Cava Cornovo Est), active open pit quarry at 860 m a.s.l.; Mergozzoni quarry (Cava Mergozzoni or Cava dei Mergozzoni), abandoned open pit quarry at 950 m a.s.l.

View of the Madre quarry (Cava Madre), Candoglia, Ivrea Verbano, Italy. From Sesia Valgrande Geopark.

Panoramic view from the Madre quarry (Cava Madre), Candoglia, Ivrea Verbano, Italy. From Duomo di Milano.

The candoglia marble consist of lenses of calcite and calc-silicate marbles, interlayered within the kinzigites of the Ivrea-Verbano Zone, with a subvertical attitude and small thickness (8-30 m). Structural studies evidenced isoclinal folds, with subvertical axial plane parallel to the main foliation, which connect the different small lenses. Since 1387 the Candoglia marble quarries belong to the "Veneranda Fabbrica del Duomo" of Milan and now the produced stone (about 1000 t/year) is only used for the restoration of the Milan cathedral. The Candoglia marble was also used in the past as facing stone in few other monuments such as Certosa in Pavia, Cappella Colleoni in Bergamo, and San Petronio Cathedral in Bologna. The medium to coarse-grained Candoglia marble mainly shows a pink colour with frequent dark green layers, due to the presence of diopside and tremolite; other subordinate minerals are quartz, epidote, sulphides, Ba-feldspars, baryte, and rare phlogopite. The varieties of Candoglia marble (pink, white, grey, and veined) are deeply affected by the chromatic, textural, and compositional features. Madre quarry (Cava Madre) is the type locality for taramellite and paracelsian; Mergozzoni quarry (Cava Mergozzoni or Cava dei Mergozzoni) is the type locality for wenkite.

Polished Candoglia marble with dark calc-silicate layers.

Polished Candoglia marble with dark calc-silicate layers.

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
Taramellite (bronze brown) and calcite in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown) and calcite in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown) calcite and green chlorite in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)
Taramellite (bronze brown) calcite and tremolite (green) in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown) calcite and tremolite (high interference colors) in a marble. Candoglia, Ivrea Verbano, Italy. XPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown) calcite and tremolite (green) in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)
Taramellite (bronze brown) calcite, chlorite and tremolite (green) in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown) calcite, chlorite and tremolite (high interference colors) in a marble. Candoglia, Ivrea Verbano, Italy. XPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown) calcite, chlorite and tremolite (green) in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)
Taramellite (bronze brown) calcite, chlorite and tremolite (green) in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown) calcite, chlorite and tremolite (high interference colors) in a marble. Candoglia, Ivrea Verbano, Italy. XPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown) calcite, chlorite and tremolite (green) in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)
Taramellite (bronze brown), calcite, tremolite and chlorite (green) crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown), calcite, tremolite and chlorite (high interference colors) crystals in a marble. Candoglia, Ivrea Verbano, Italy. XPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown), calcite, tremolite and chlorite (green) crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)
Taramellite (bronze brown), calcite, tremolite and chlorite (high interference colors) crystals in a marble. Candoglia, Ivrea Verbano, Italy. XPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown), calcite, tremolite and chlorite (green) crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)	Taramellite (bronze brown), calcite, tremolite and chlorite (green) crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 10x (Field of view = 2mm)
Taramellite (bronze brown) and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 20x (Field of view = 1mm)	Taramellite (bronze brown) and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. XPL image, 20x (Field of view = 1mm)	Taramellite (bronze brown) and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 20x (Field of view = 1mm)
Taramellite (bronze brown) and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 20x (Field of view = 1mm)	Taramellite (bronze brown) and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 20x (Field of view = 1mm)	Taramellite (bronze brown) and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. XPL image, 20x (Field of view = 1mm)
Taramellite (bronze brown) and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 20x (Field of view = 1mm)	Taramellite (bronze brown), tremolite and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 20x (Field of view = 1mm)	Taramellite (bronze brown), tremolite and calcite crystals in a marble. Candoglia, Ivrea Verbano, Italy. PPL image, 20x (Field of view = 1mm)