Quartz veins from the Martha Hill epithermal gold-silver deposit, Waihi, commonly exhibit crustiform banded textures.
Visual differences observed between bands are primarily the result of a 1 to 1500 m variation in quartz grain size. Quartz
band textures are dominated by anhedral interlocking quartz mosaics, commonly associated with minor adularia and sulfide
phases; these textures are interpreted to be products of amorphous silica crystallisation. The occurrence of rhombic adularia
suggests that prolonged boiling influenced parent fluids. In contrast, the presence of coarsely crystalline bands, made up of
subhedral to euhedral quartz grains, infers primary crystal growth from solution; evidenced by the occurrence of growth-zoned
quartz within these bands. There is a narrow range of 3.3%o in 618Oq,,,,,= between maximum and minimum isotopic values
for the deposit. Significant overlap in 618Oqu,, values are observed between the Martha and Welcome lodes. However,
statistically significant and commonly systematic differences do occur between individual bands analysed in most samples.
Temperature fluctuations may be the dominant factor responsible for observed inter-band variation.