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- Title
NEPHRITE JADE FROM VAL MALENCO, ITALY: REVIEW AND UPDATE.
- Authors
Adamo, Ilaria; Bocchio, Rosangela
- Abstract
Alpe Mastabia, in the Val Malenco district of northern Italy, has been a source of nephrite jade since the early 2000s. Twenty-one samples from this locality were investigated by classical gemological methods; X-ray powder diffraction, combined with quantitative phase analysis; scanning electron microscopy in combination with energy-dispersive spectrometry; electron microprobe analysis; mass spectrometry; and mid-infrared spectroscopy. From a mineralogical standpoint, this jade consists mainly of tremolite amphibole, with variable amounts of other constituents, especially calcite (up to approximately 30 wt.%), but also pyroxene, apatite, and sulfide minerals. Its pale green color is related to the low iron content of the tremolite amphibole, whereas the other minerals are responsible for different colors (calcite for white, molybdenite and galena for gray). On the basis of minor and trace-element composition, we can classify this jade as dolomite-related nephrite (para-nephrite). Although new material could be recovered from this area, future production will probably be limited by access difficulties.
- Subjects
MALENCO Valley (Italy); JADE; X-ray powder diffraction; PYROXENE; APATITE; AMPHIBOLES; TREMOLITE; SCANNING electron microscopy
- Publication
Gems & Gemology, 2013, Vol 49, Issue 2, p98
- ISSN
0016-626X
- Publication type
Article
- DOI
10.5741/GEMS.49.2.98