Wondering What This Is Called (in Terms Of An 'identification' Name)? Found In North Island Around Auckland/coromandel, New Zealand.

[motl57]

I was thinking quartzite maybe (see first and last photo especially; the isolated crystals in photo 4 would then be quartz if its quartzite), but don't know what the covering is, nor the other layers present. Also some parts appear like small blebs (eg photo 2) and there is a green mineral present (maybe green patina copper?) (photo 3 and 7).

Is rather hard (some parts don't scratch with metal, but others - back covering (eg photo 6) are softer and do scratch slightly with metal) and does not fizz in contact with mild acid (vinegar).

Thanks ?