Chrome chalcedony comes from near the town of Newman in the Pilbara region of Western Australia which is approximately 1,100 kms. north of the capital, Perth.
The geological setting of the occurrence is that of an ultramafic intrusion into an area of granite-greenstone of Archaean age(>2500Ma)
The intrusion consists of serpentinite that has also produced chrysoprase, chalcedony & common opal. These rock types along with the chrome chalcedony occur in the weathered , silicified cap rock.
It is believed that original weathered serpentinite has been replaced through processes of silica deposition and the chrome chalcedony represents a whole-rock replacement or psuedomorph.
Chromium which is responsible for the green colouration of the chalcedony has originated from the existence of chromite within the serpentinite.