540 - Høgtuvaite

ID	540
Mineral	Høgtuvaite
Location	Bordvedåga - Høgtuva - Nordland - Norway
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Høgtuvaite information at mindat.org

ID	1917
Long ID	1:1:1917:6
Formula	`Ca₄[Fe²⁺₆Fe³⁺₆]O₄[Si₈Be₂Al₂O₃₆]`
IMA Status	0
General Appearance	Black, elongate, poikiloblastic crystals up to 4 cm long.
Occurrence	In a Proterozoic peraluminous granitic gneiss.
Discovery Year	1983
Diapheny	Opaque
Cleavage	In two directions, intersecting at ~55°.
Tenacity	brittle
Colour	Black
Hardness (min)	5.5
Hardness (max)	5.5
Luminescence	Nonfluorescent
Lustre	Vitreous
About the name	Named for the Høgtuva peak, the nearest significant reference point in the area of the type locality in Nordland, Norway. The peak is located about 7 km NW of the TL. It was first found in 1983 by Ingvar Lindahl (Norwegian Geological Survey) during uranium exploration in the area, and named by Grauch et al. (1994).
Streak	Grey-green
Crystal System	Triclinic
Cleavage Type	Distinct/Good
Fracture type	Irregular/Uneven
Twinning	Ubiquitous polysynthetic twinning; twin axis perpendicular pseudomonoclinic (010).
Publication Year	1994
key_elements	0
shortcode_ima	Htu
Group	Rhönite Group

Høgtuvaite