Gold and Silver bearing epithermal veins of the Golden
Cross deposit are hosted in Miocene and Pliocene calc-alkaline volcanics
occurring 8
km northwest of Waihi at the southern extent of the Coromandel Peninsula,
North Island, New Zealand. Veining occurred during a period of hydrothermal
activity that began early to late Pliocene, and possibly continued into the
Pleistocene.

Field relations and
petrographic relationships reveal that multiple generations of FeS2 occur in the Golden Cross region,
with FeS2
occurring in
all nine rock types recognised at Golden Cross. The variability of
FeS2 morphology was investigated by preparation of
high purity FeS2 separates, and grain
counting. Marcasite is the dominant FeS2 phase at Golden Cross, and
along with pyrite is shown to have a systematic habit variation. Pyrite shows a
sequence from cubes through octahedra to pyritohedra to dendritic growth. This
pyrite sequence conforms to an experimentally determined sequence. The parallel
sequence for marcasite at Golden Cross is from tabular through bladed aggregates
to euhedral miscellaneous marcasite morphologies. The FeS2 sequences observed are
believed to be due to increasing temperature, and perhaps also increasing
FeS2-oversaturation and
fluid flow.