The smaller Lava Plains field differs markedly from the Anakie
field in that the basalts that host the sapphires are very much
in evidence on the field.
The field lies within one of several major basalt provinces in
north-eastern Queensland, the McBride Basalt Province.
Sapphires occur in eruptive volcanics from a limited number of
vents and are recovered from the eluvium, colluvium and alluvium
within and adjacent to present day watercourses in the vicinity
of the vents.
The sapphires occur in brown and black clayey soils containing
vesicular basalt rock fragments and basalt cobbles and boulders.
Associated minerals found in the wash include zircon, ilmenite,
olivine, hematite and feldspar.
The main areas mined are centred on Wyandotte Creek and Mines
genuine sapphire -
made by nature
Resource on the Australian Sapphire Industry