Offretite, Limberg bei Sasbach, Kaiserstuhl, Baden (Germany) | |
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Offretite is a very common mineral at Limberg, mainly at Quarry I. This species was for a long time only known from Mont Semiol, Loire, France. The Limberg was one of the earliest other locations, described by Rinaldi et al. (1975). Since then Offretite has been found on numerous other locations worldwide. Offretite crystals and aggregates are typical very small, only a few tenth´s of a millimeter and this may be the reason together with the difficulty to determine it, why its presence in many locations was not recognized in the past. For many years also the Offretite from Limberg was considered as intergrowth with the very similar Erionite due to optical differences in the crystals, but recent investigations by WEISENBERGER & SPÜRGIN (2009) have shown that there is no substantial amount of Erionite present. Offretite, always very small forms different aggregates and habits which are shown below. | |
Limberg Faujasite Phillipsite Chabazite Offretite Hyalite Dolomite Calcite Aragonite Montmorillonite Paragenesis Literature |
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Home | Shaving brush like aggregates of Offretite about 0,2 mm long from Quarry I. |
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Offretite as radiating aggregates with some Hyalite. Field of view about 1 mm. | Aggregates of Offretite in Montmorillonite. Field of view about 1 mm. |
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Barrel-shaped Offretite. Field of view about 1 mm. | Offretite-Aggregates on blue-black colored Montmorillonite. Field of view about 1 mm mm |
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Reare shaving-brush like aggregate about 0.5 mm long. | Clear hexagonal prisms of Offretite. Field of vie about 1 mm. |
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Coated aggregates of Offretite Montmorillonite. Field of view about 0.8 mm. |
Offretite with Phillipsite -hemispheres. Field of view about 1.2 mm. |
A vug in the Limburgite with small radiating aggregeates of Offretite. Field of view about 12 mm |
The Limberg at Mindat.org | The Limberg as a Geotope with a map | The Limberg for tourists |