You know, the metric weight of a cloth doesn't often come up, the way we work, with the smaller mills. Maybe we just never ask ...
It is mid- to heavy-weight, and very dense, and a little on the dry and hairy side. Still, a little softer than your typical Harris tweed, such is the nature of the yarn and the type of finishing.
I would say 500-500gsm, but I will ask the mill (about time) to get an exact measurement.