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Nordstrandite from Guam

Nature

By:
and
DOI: 10.1038/196265a0

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Abstract

NORDSTRANDITE (Al2O3??3H2O), previously reported only as a synthetic product1,2, occurs in Miocene limestone on Guam. In south Guam this limestone forms a cap several hundred feet thick, on the Mount Alifan-Mount Lamlan ridge, and overlies late Eocene and early Miocene basalt flows and volcanic conglomerates. The volcanic rocks below the limestone are deeply weathered. The nordstrandite occurs in secondary solution cavities and is concentrated mainly in the basal part of the limestone near its contact with the weathered basalt. In thin section the nordstrandite crystals are seen as flamboyant aggregates reaching lengths of as much as 0.4 mm. The optical properties of the mineral are as follows: ?? = 1.580 ?? 0.004 colourless optic sign = positive ?? = 1.580 ?? 0.004 colourless 2 V = low ?? = 1.596 ?? 0.004 colourless elongation = negative ??-?? = 0.016 extinction = inclined The hardness is about 3 and the specific gravity was determined by Edward J. Young to be 2.436. ?? 1962 Nature Publishing Group.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Nordstrandite from Guam
Series title:
Nature
DOI:
10.1038/196265a0
Volume
196
Issue:
4851
Year Published:
1962
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Nature
First page:
265
Last page:
266