Australian Museum Journal Epigenetic common opal from the Hawkesbury Sandstone Formation of the Sydney Basin

Shortform:
Lovering, 1952, Rec. Aust. Mus. 23(1): 29–32
Author(s):
Lovering, J. F.
Year published:
1952
Title:
Epigenetic common opal from the Hawkesbury Sandstone Formation of the Sydney Basin
Serial title:
Records of the Australian Museum
Volume:
23
Issue:
1
Start page:
29
End page:
32
DOI:
10.3853/j.0067-1975.23.1952.619
Language:
English
Plates:
plate iv
Date published:
16 June 1952
Cover date:
16 June 1952
ISSN:
0067-1975
CODEN:
RAUMAJ
Publisher:
The Australian Museum
Place published:
Sydney, Australia
Digitized:
22 April 2009
Available online:
22 July 2009
Reference number:
619
EndNote package:
EndNote file
Title page:
Title page (141kb PDF)
Complete work:
Complete work (863kb PDF)

Abstract

An unusual occurrence of epigenetic common opal, apparently derived from the normal ground-waters of the Hawkesbury sandstone formation of the Sydney Basin, is described. The opal forms simple and botryoidal incrustations, simple and coralloidal stalactitic structures and also is deposited on stalactites of lamellar limonite. Refractive index values vary widely and haphazardly between 1.414 and 1.443.