Sorensenite
Na₄SnBe₂Si₆O₁₈^.2H₂O
Monoclinic. Point Group: 2/m
Cell Data: Space Group: C2/c    Z = 4

The chemically peculiar sorensenite is unique to Ilímaussaq, but locally abundant. Masses up to 10 cm across are known. It occurs in sub-parallel to slightly divergent aggregates of slender prismatic crystals.

Most sorensenite is white to pale pink in aggregate; some is distinctly pink. Thin areas of the prismatic crystals are often transparent and colorless.

Sorensenite. Daylight at left and shortwave ultraviolet at right. Specimen width 8 cm.

Under shortwave ultraviolet sorensenite fluoresces cream, white, or bluish-white, and with variable intensity. Some is moderately bright; much is dim. Sorensenite does not fluoresce under longwave ultraviolet, but provides a faint cream to white response under midwave ultraviolet.

Sorensenite can be found with several other fluorescent species, including tugtupite (Kvanefjeld location) and films of bright green, uranyl-activated fluorescent minerals (shortwave ultraviolet).

Sorensenite in platy masses fluorescing cream with a uranyl-activated green-fluorescing mineral under shortwave ultraviolet. Field width 6 cm.

This page edited: June 06, 2005.