Nonndorf bei Raabs, Raabs an der Thaya, Waidhofen an der Thaya District, Lower Austria, Austria

Very small hexagonal prisms (20 micron) consisting of rhabdophane-(Y) (bright grey core) with an overgrowth of rhabdophane-(Ce) (bright), in a void filled with tiny fibrous cryptomelane crystals (the grey matrix, seen on the left side, is dense cryptomelane). SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This ...

© Uwe Kolitsch

Hollandite with fine concentric layering. The darker bands are softer and contain more Al and Fe than the brighter bands. SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, ...

© Uwe Kolitsch

Fine-grained hollandite matrix (black) containing more or less rounded colourless, transparent inclusions of quartz and K-feldspar. The rounded shape is probably due to fluvial transport. Optical micrograph of the surface of the polished section. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, ...

© Uwe Kolitsch

Spherulitic aggregates of hollandite (black) associated with more or less rounded colourless, transparent inclusions of quartz and K-feldspar. The rounded shape is probably due to fluvial transport. Optical micrograph of the surface of the polished section. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) ...

© Uwe Kolitsch

Fine-grained cryptomelane (black), with hair-like inclusions of a kaolinite-subgroup mineral (very bright). Optical micrograph of the surface of the polished section. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, ...

© Uwe Kolitsch

Slightly inhomogeneous, Ba-bearing cryptomelane (the darker areas contain more Fe and less Ba). SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, ...

© Uwe Kolitsch

Hair-like fibrous mineral of the kaolinite subgroup (dark) in a matrix of cryptomelane (bright grey). SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, ...

© Uwe Kolitsch

Hollandite with fine concentric layering. The darker bands are softer and contain more Al and Fe than the brighter bands. SEM micrograph (SE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, ...

© Uwe Kolitsch

Fine-grained hollandite matrix (grey) containing rounded inclusions of quartz (dark) and K-feldspar (dark grey; partly intergrown with quartz). The rounded shape is probably due to fluvial transport. SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. ...

© Uwe Kolitsch

Hair-like fibrous mineral of the kaolinite subgroup (dark) in a matrix of cryptomelane (bright grey). SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, ...

© Uwe Kolitsch

Inhomogeneous fine-grained cryptomelane (black), with crack-fillings also of cryptomelane. Optical micrograph of the surface of the polished section. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, Rhabdophan-(Ce), ...

© Uwe Kolitsch

Slightly inhomogeneous, Ba-bearing cryptomelane (the darker areas contain more Fe and less Ba). SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, ...

© Uwe Kolitsch

Overview of the rhabdophane-(Y)-rhabdophane-(Ce) crystal aggregate. This was the only aggregate found in the whole polished section. Very small hexagonal prisms (20 micron) consisting of rhabdophane-(Y) (bright grey core) with an overgrowth of rhabdophane-(Ce) (bright), in a void filled with tiny fibrous cryptomelane crystals (the grey matrix, ...

© Uwe Kolitsch

Hair-like fibrous mineral of the kaolinite subgroup (dark) in a matrix of cryptomelane (bright grey). SEM micrograph (SE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, ...

© Uwe Kolitsch

Fine-grained hollandite matrix (grey) containing rounded inclusions of quartz (dark) and K-feldspar (dark grey; partly intergrown with quartz). The rounded shape is probably due to fluvial transport. SEM micrograph (SE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. ...

© Uwe Kolitsch

Fine-grained hollandite matrix (pale grey) containing more or less rounded colourless, transparent inclusions of quartz and K-feldspar (grey). The rounded shape is probably due to fluvial transport. Reflected-light micrograph of the surface of the polished section. (Note this looks very similar to an SEM image.) This material was described ...

© Uwe Kolitsch

Small rounded, detrital zircon grain (bright) with dissolved core, in a matrix of cryptomelane (bright grey). SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, ...

© Uwe Kolitsch

Inhomogeneous fine-grained cryptomelane (grey), with crack-fillings also of cryptomelane. The minor dark grey inclusions are quartz and/or K-feldspar. Reflected-light micrograph of the surface of the polished section. (Note this looks very similar to an SEM image.) This material was described in: Kolitsch, U. and Schillhammer, H. (2024): ...

© Uwe Kolitsch

Strongly altered prismatic rutile crystal (40 micron; grey), associated with micaceous muscovite (dark), in hollandite matrix (bright grey) containing grains of quartz (dark; bottom left and right). SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. ...

© Uwe Kolitsch

Tiny, thin platy baryte crystals (white) in a hollandite matrix (grey). This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, Rhabdophan-(Ce), Rhabdophan-(Y), Rutil und Zirkon in Manganoxid-Knollen in der Nähe von Nonndorf, ...

© Uwe Kolitsch

Hair-like fibrous mineral of the kaolinite subgroup (dark) in a matrix of cryptomelane (bright grey). SEM micrograph (SE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, Quarz, ...

© Uwe Kolitsch

Fine-grained hollandite matrix (grey) containing rounded inclusions of quartz (dark) and K-feldspar (dark grey; partly intergrown with quartz). The rounded shape is probably due to fluvial transport. SEM micrograph (BSE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. ...

© Uwe Kolitsch

Small rounded, detrital zircon grain (bright grey) with dissolved core, in a matrix of cryptomelane (grey). SEM micrograph (SE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein Kaolinitgruppenmineral, Kryptomelan, Muskovit, ...

© Uwe Kolitsch

Strongly altered prismatic rutile crystal (40 micron; dark grey), associated with micaceous muscovite (dark), in hollandite matrix (grey) containing grains of quartz (dark; bottom left and right). SEM micrograph (SE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. ...

© Uwe Kolitsch

Fine-grained hollandite matrix (grey) containing rounded inclusions of quartz (dark) and K-feldspar (dark grey; partly intergrown with quartz). The rounded shape is probably due to fluvial transport. SEM micrograph (SE mode) of a polished section of a manganese oxide nodule. This material was described in: Kolitsch, U. and Schillhammer, H. ...

© Uwe Kolitsch

Fine-grained cryptomelane (grey), with hair-like inclusions of a kaolinite-subgroup mineral (nearly black). Reflected-light micrograph of the surface of the polished section. (Note this looks very similar to an SEM image.) This material was described in: Kolitsch, U. and Schillhammer, H. (2024): 2315) Hollandit, Kalifeldspat, ein ...

© Uwe Kolitsch

Spherulitic aggregates of hollandite (pale grey) associated with more or less rounded colourless, transparent inclusions of quartz and K-feldspar (both grey). The rounded shape is probably due to fluvial transport. Reflected-light micrograph of the surface of the polished section. (Note this looks very similar to an SEM image.) This material ...

© Uwe Kolitsch