The minerals of the abandoned Mn-mine of Falotta

Minerals at Falotta

Albite NaAlSi₃O₈ Albite is one of the most common minerals. It occurs as colourless crystals, size from 0.2 -5 mm length in small crevasses and clefts. Normal shape, often twins. Anatase TiO₂ Anatase occurs as a rare accessory mineral together with quartz and albite in thin fractures of the radiolarite. The colour is yellow to fair brown, its habit is bipyramidal and the size up to 0.3 mm.
Aragonite CaCO₃ Aragonite is a common mineral. It occurs as white to colourless crusts. As single crystals, or often as long slender needles aggregated to sprays in small vugs. The size of the aggregates is up to 16 mm across. Arseniosiderite Ca₂Fe³⁺₃(AsO₄)₃O₂ • 3H₂O Tabular crystals of red colour. Crusty aggregates of several mm diameter, is accompanied by quartz, albite, tripuhyite and kemmlitzite. Arsenogoyazite (Sr,Ca,Ba)Al(AsO₄)(AsO₃OH)(OH)₆ Arsenogoyazite is a frequent mineral, however, it will often be overlooked. It appears as xenomorphe grains in cabalzarite, as white small bands to several mm of length or rarely as pseudo rhombic crystals in small gaps. Bergslagite CaBe(AsO₄)(OH) Bergslagit is a very rare mineral, its crystals are tabular, pseudo rhombic and colourless transparent. Size up to 0.6 mm. Birnessite Na₄Mn₁₅O₂₇ • 9H₂O Birnessite is a secondary manganese oxide and appears in form of tiny black crystals and grains. Brandtite Ca₂(Mn,Mg)(AsO₄)₂ • 2H₂O Brandtite occurs as white to colourless massive shists, as crystals of 2 cm in length and 1 - 3 mm thick, combined to sub parallel to radial aggregates embedded in gaps of braunite together with grischunite, sarkinite, geigerite, tilasite and manganese-berzeliite or as a lawn of white crystals of some mm size. Braunite Mn²⁺Mn³⁺SiO₁₂ Braunite is the manganese ore exploited at Falotta. It occurs as tiny, pseudooktahedral bipyramids of 0.1 mm size. Cabalzarite Ca(Mg,Al,Fe)₂(AsO₄)₂ • (H₂O,OH) Although the occurrence of cabalzarite is restricted to a 1m²outcrop,the mineral displays a broad range of morphologies. The colour is light-brownish to salmon pink or orange brown. Isolated crystals up to 1 mm in size. The largest crystals look like axinite (wedge shaped), and their faces are often curved. Complex crystalline aggregates, up to 2 mm in length, located in vugs. Fibrous to tabular crystals up to 3 mm in length, forming radiating aggregates up to 5 mm in diameter. These aggregates are developed in two dimensions within thin fractures, and form spheroids where sufficient space was given. Aggregates of parallel needles filling veinlets up to 2 mm thickness, associated with massive quartz, carbonate and fibrous sursassite. Under this habitus, cabalzarite may be mistaken for the silicate sursassite. In vugs, cabalzarite is associated with crystals of quartz, adularia, kutnahorite, tilasite, grischunite and arseniosiderite, with sprays of fine needles of tripuhyite, black crusts of Rancieit-Takanelith and with Arsenogoyazit. The mineral has been named cabalzarite as a tribute to Walter Cabalzar, a keen amateur collector who performed an important contribution to the mineralogy of the canton Graubünden. Falotta is type locality. Calcite CaCo3 Calcite occurs as white to colourless, scalenohedral and rhombohedral crystals often covered with manganese oxides. The crystals are up to 3 mm long. Chalcedony SiO2 microscopically crystallized variety of Quartz Chalcedony has been found as white balls of 1 - 2 mm diameter and as resinous crusts. Clinochlore (Mg,Fe)5Al(Si3Al)O10(OH)8 The clinochlore from the Falotta quarry is containing traces of manganese, due to that its colour is red brown. The mineral occurs as small nodules of 0.5 mm size. Fuchsite Fuchsite is a chromium containing variety of muscovite. It occurs as green, micaceous coverage on or as inclusions in radiolarite. Geigerite Mn₅(AsO₄)₂(AsO₃OH)₂ • 10H₂O Geigerite is a colourless, white to pink mineral. It occurs as wedge-shaped crystals or as white tuffs of up to 0.5 mm size together with other rare arsenate minerals mostly on brandtite. The mineral is named in honour of the mineralogist Dr. Thomas Geiger, in recognition of his contribution to the mineralogy of the Oberhalbstein and in particular the Falotta mine. Type locality Falotta. Grischunite NaCa₂Mn²⁺₅Fe³⁺(AsO₄)₄ • 2H₂O Grischunite occurs in small platy crystals up to 1 mm of dark red brown colour, partly as anhedral grains, or in well-developed lathlike crystals, elongated along the b-axis or as lawn of crude, elongated crystals up to 7 mm in length. Grischunite is associated with brandtite, sarkinite, geigerite, kutnahorite, manganoan-berzeliite, manganoan calcite and tilasite. The name grischunite was chosen after the roman name Graubünden, Grischun. Type locality is Falotta. Hematite Fe³⁺₂O₃ Hematite is of minor importance, it occurs as bad developed plates embedded in massive tinzenite, and its size is up to 2 mm. Illite K(Al,Mg,Fe)₂[(OH)₂I (Si,Al)₄O₁₀] • nH₂O Illite is known as white to pink, soapy filling embedded in calcite, manganoan calcite and brandtite. Kemmlitzite SrAl₃(AsO₄)(SO₄)(OH)₆ Kemmlitzite was originally described as hidalgoite. It occurs as trigonal, pseudo cubic, colourless to white crystals of 0.2 to 3 mm. Kemmlitzite is found together with albite, quartz, cabalzarite, tripuhyite, tilasite and arseniosiderite. Konichalcite CaCu(OH/AsO)₄ Green coatings, seldom orthorhombic crystals of about 1 mm size. Very rare. Kutnahorite Ca(Mn,Mg,Fe)(CO₃)₂ Occurring as 0.5 -1 mm, saddle like, white crystals together with brandtite, tilasite, sarkinite and grischunite. Lindbergite Mn(C₂O₄) • 2H₂O Lindbergite is a Mn oxalate. It occurs as white short prismatic crystals of 1 x 0.5 mm in size on small crystals of quartz together with braunite and other Mn-minerals. (Look at "ship-like mineral" Schweizer Strahler 1984, S. 433) Manganberzeliite (NaCa)₃(Mn,Mg)₂(AsO₄)₃ It has been found as crude to well formed garnet like crystals of yellow to orange-yellow or brown yellow colour and up to 0.5 mm in size. The mineral is very brittle and good crystals are extremely rare. Muskovite KAl₂(AlSi₃)O₁₀(OH,F)₂ Occurs as small white to colourless aggregates. Associated minerals include albite, quartz, sursassite and piemontite.		Aragonite-aggregate, 16 mm across.
		Aragonite spray, 1.5 mm across.
		Arseniosiderite-aggregate, 0.8 mm across.
		Arsenogoyazite, length of the lath 10 mm.
		Piece of massive brandtite, 10 mm across.
		Group of yellowish calcite rhombohe- drons, 3.5 mm across.
		Salmon pink cabalzarite crystals, 3 mm across.
		Aggregate of nearly white cabalzarite needles, 2.5 mm across.
		Nodules of brown clinochlore, 2 mm across.
		Grischunite crystal of 0.5 mm in length.
		Lawn of crude, elongated grischunite crystals up to 8 mm in length.
Due to inclusions red coloured kemmlitzite crystals 0.8 mm across.	Pseudo cubic kemmlitzite crystal of 0.4 mm.	Lindbergite crystal of 0.5 mm length
Opal (Hyalite) SiO₂ • nH₂O Colourless resinous aggregates on tinzenite of 0.3 mm in size. Parsettensite KMn₆Al₇Si₈O₂₀ • 2H₂ Parsettensite is a member of the mica group and relatively common. It occurs mostly as mica-Iike blades together with tinzenite, quartz, sursassite, piemontite, rhodonite, manganoan calcite, albite. The colour is brown to copper red. Piemontite-(Sr) Ca₂(AlMn³⁺)₃(SiO₄)₃OH Piemontite is a mineral of the epidote group and occurs as inclusion in quartz veins. It has also been found as wine red needles, up to 5 mm in length, in cavities together with quartz crystals. Quartz SiO₂ Is very common and occurs as crystals up to 3 cm. Very interesting are inclusions of braunite, haematite, radiolarite, piemontite, tinzenite and tripuhyite. Often nice phantoms with inclusions of radiolarite can be observed. Rancieite(Ca,Mn²⁺)Mn⁴⁺₄O₉•3H₂O -Takanelith (Mn²⁺,Ca)Mn⁴⁺₄O₉•H₂O The secondary manganoan-oxide is present as a mixture of rancieite-takanelite is very common and occurs as black, brown to silvery crusts or as acicular sprays and tufts of some mm in size.		Vitreous, resinous aggregate of hyalite on tinzenite of 1.5 mm across.
		Piece of massive parsettensite, 30 mm in size.
Quartz with inclusions of sursassite, 2.5 mm width.	Olive brown sprays of rancieite- takanelith crystals, 2 mm across.	Massive rhodochrosite, 20 mm width.
Rhodochrosite (Mn,Ca)CO₃ This mineral is very rare and occurs as white to pink crystals together with manganoan calcite. Its size is up to 0.2 mm. Rhodonite Mn₅Si₃O₁₃ Rhodonite is very common in lenses up to 80 cm, crossed by veins of manganoan calcite, parsettensite, tinzenite, quartz and braunite. The surface is due to oxidation black. Crystals are very rare and of salmon red, pink or red brown colour, translucent and seldom transparent.		Acicular rhodonite crystals in a small vug, 2.5 mm across.
Sharp pointed sarkinite crystal of 1 mm in length.	Aggregates of acicular sursassite, 4 mm across.	Thin talmessite plates forming compact rosettes. The rosette is about 11 x 16 mm in size.
Sarkinite Mn₂(AsO₄)(OH) Brown often pink, bundles of spear like crystals of 0.2 to 2 mm length. Sarkinite is associated with brandtite, grischunite, tilasite, kutnahorite, manganoan-berzeliite and manganoan calcite. Spessartine Mn₃Al₂(SiO₄)₃ Spessartine was found in association with rhodonite, parsettensite, manganoan calcite and braunite. The mineral occurs solid, as grains and seldom as crystals up to 0.5mm. Sursassite-(Sr) Mn₂Al₃(SiO₄)(Si₂O₇)(OH)₃ Sursassite is very common and occurs as veins of parallel grown needles or as aggregates of fibbers of 2 to 3 mm length together with calcite in small vugs. Its colour is copper red. Talmessite Ca₂Mg(AsO₄)₂ • 2H₂O Dirty white crystals, aggregated to rosettes of several cm in size. Tilasite CaMg(AsO₄)F Colourless, white, greenish or pink prismatic to fan shaped crystals with frosted terminations of 1 to 4 mm size. Tilasite is a common mineral.		Colourless tilasite aggregates, 3 mm across.
		Cleavage with radiating todorokite, 5 mm across.
Tripuhyite crystal spray of 0.8 mm diameter.	Radiating tripuhyite aggregate 6 mm in hight.	Unknown mineral: Tiny red crystals, 0.8 mm across.
Tinzenite (Ca,Mn,Fe)₃Al₂BSi₄O₁₅(OH) Tinzenite is a variety of axinite, it occurs as yellow to brownish veins or crystals up to 3 mm in vugs of banked rhodonite. Todorokite (Mn²⁺,Ca,Mg)Mn⁴⁺₃O₇ • H₂O Todorokite occurs along cleavages as black to brown-black sprays of several millimetres size. Tripuhyite FeSb₂O₆ It occurs as yellow, acicular spays and tufts with needles of 0.5 mm rarely as radiating aggregates up to 6 mm in diameter. Tripuhyite is associated with arseniosiderite, cabalzarite, grischunite, quartz and albite. Wallkilldellite Ca₂Mn₃²⁺(AsO₄)₂(OH)₄•9H₂O Brown, mica-like masses together with white blades of brandtite. Unknown mineral Mn(C₂O₄) • 3H₂O Is a Mn oxalat. It occurs as excellent, colourless transparent crystals of about 1 mm in length. It converts due to dehydration to the Mn oxalat lindbergite Mn(C₂O₄) • 2H₂O. (Information Prof. Dr. Stefan Graeser, Mineralogical Institute of the University of Basel) Unknown mineral Mn²⁺Mn³⁺₂(OH)(AsO₄)₂ •4H₂O Tiny red crystals up to 0.2 mm embedded in brandite together with grischunite, tilasite and sarkinite. (Information Prof. Dr. Thomas Armbruster, University of Bern)
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