Abstract

An interesting diamond crystal from this field was lent by Mr. D. A. Porter for measurement and description. The diamonds at this locality are found in deposits of sand and gravel, probably of Pliocene age, underlying the basalt capping of a number of isolated hills; they are accompanied by stream tin and a little gold.

The crystal weighs 0.0443 grams. It is colourless, and consists of a hexakis-octahedron with indices near (111), twinned on an octahedral face (spinel law), and flattened parallel to the twin plane to form a triangular plate; diamonds of this shape are known at Amsterdam as naadsteenen (suture stones). Only six faces of each half of the twin are developed, forming a very low pyramid with curved edges and planes, each face striated in lines running roughly parallel to its intersections with an octahedral face, but towards the periphery the striations curve in conformity with the crystal edges and gradually disappear. A few small triangular depressions appear near the apex, the corners of the pits, as is usual in natural etch pits of the diamond, being directed towards an adjacent octahedral edge.

 
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Bibliographic Data

Short Form
Anderson, 1922, Rec. Aust. Mus. 13(5): 201–212
Author
C. Anderson
Year
1922
Title
Mineralogical notes. No. XI. Diamond
Serial Title
Records of the Australian Museum
Volume
13
Issue
5
Start Page
201
End Page
212
DOI
10.3853/j.0067-1975.13.1922.873
Language
English
Plates
plates xxxviii–xli
Date Published
15 March 1922
Cover Date
15 March 1922
ISSN
0067-1975
CODEN
RAUMAJ
Publisher
The Australian Museum
Place Published
Sydney, Australia
Subjects
MINERALOGY; GEM STONES
Digitized
08 January 2009
Available Online
06 March 2009
Reference Number
873
EndNote
/Uploads/Journals/17098/873.enw
Title Page
/Uploads/Journals/17098/873.pdf
File size: 86kB
Complete Work
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