The Val Boschetto deposit is a small nickel occurence in black serpentinite with a mineral combination which is rare in Switzerland. It was not mined, only some exploration drilling was done in the 1960ies. The ore itself consists of tiny droplets of mainly pentlandite cemented by magnetite. Additionally awaruite, heazlewoodite and native copper can be observed in the droplets. Heazlewoodite was confirmed by REM/EDX as it is difficult to recognize under the ore microscope.
Polished slab. Width: 12 cm
A typical droplet of pentlandite and magnetite. Polished section with Nic //, Obj. 20x, air. (Scale bar: 100 µm):
Awaruite (middle), pentlandite (top, bottom); Nic //, Obj. 50x, air:
Native copper in awaruite, Nic //, Obj. 125x, oil:
Awaruite possibly mixed with heazlewoodite, pentlandite (right) and three grains of native copper. Note the structure! Nic //, Obj. 125x, oil:
Haezlewoodite in pentlandite in a repolished sample from REM/EDX, Nic //, Obj. 50x, air, 50 µm bar. The reflection curves of both are very similar with a maximum difference of about 7% at 400 and 500 nm. At the rest of the visible spectrum the difference in reflection is just 2-3%.
For further informations on the region this article might be interesting:
Quervain, F. de: Das Nickelerzvorkommen Val Boschetto im Centovalli (Tessin). Schweizerische mineralogische und petrographische Mitteilungen.47.(1967).633-641.