(Overngruve (Overntjern))
A serpentine-magnesite deposit quarried for magnesite and serpentine.
Now abandoned.
The name Overntjern is often used for the quarry (Overngruve), although Overntjern is in fact a small, unmined serpentinite outcrop nearby (close to the track leading to the Overngruve).
References:
- Jøsang, Ottar (1966): Geologiske og petrologiske undersøkelser i Modumfeltet. Norges Geologiske Undersøkelse nr 235, 91-97
- Rømming, C. & Raade, G. (1980): The crystal structure of Althausite. American Mineralogist, 65, 488-498
- Witsø, T. (1994): Sjelden dolomitt fra Overntjern. STEIN 21 (3), 193
- Raade, G. (1999): Et unikt mineralselskap av magnesiumfosfater fra magnesitt-serpentin-forekomster på Modum. Bergverksmuseets Skrift nr 15, 10-14 [in norwegian]
- Nordrum, F. S. (2000). Nyfunn av mineraler i Norge 1999-2000. Bergverksmuseets Skrift 17:59-63 [on a find of phosphoellenbergerite]
Mineral List:11 entries listed. 8 valid minerals.
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