Kanada
IRISIDESCENT AMMONITE.
Canada.
Date: Late Cretaceous period, Bearpaw-Formation (75-72 million years).
Maker/Designer: Placenticeras costatum.
Measurement: Ca. 76x61cm.
Condition B.
Provenance:
Christie's, London, 2017.
The opal-like iridescence of these ammonites from Alberta, Canada, is called ammolite and has had gemstone status since 1981. The shimmering, metallic colors were formed by the combination of millions of years of compaction and mineralization of iron, copper and silica precipitated from volcanic ash.
Arrangement after the auction.
