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ETHIOPIAN OPAL

Time left
17g 9h 49m 45s
13/11/2026 15:15:00
Estimate
€ 200,00 / 400,00
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Description

ETHIOPIAN OPAL

gr 10,31
SiO2·nH2O — amorphous mineraloid (no
crystal structure)
More information
Originating from the Wollo Province in Ethiopia
(deposit discovered in 2008), this opal is often of “hydrophane” type
(absorbs water and changes transparency). It forms by precipitation
of silica gels in cavities within Tertiary volcanic rhyolites. Its play-of-
color (opalescence) arises from light diffraction on regularly packed
silica spheres. Hardness 5.5–6.5 Mohs, density 2.0–2.2 g/cm³
A gemstone
rapidly gaining popularity in jewelry for its intense play-of-color;
highly sought by collectors for its color variety; requires special care
to prevent dehydration and crazing.
Time auction 1251

Historia Naturalis

mon 26 October - fri 13 November 2026
The description sheets do not always indicate the state of conservation of the goods, we invite you to always request the condition report before making your offers
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