In order for wool fabric to be an official Harris tweed, it must be wool from sheep raised and sheared in either Shetland, the Orkneys, on the Hebrides or any island on the western coastland of Scotland. Further, not only this, but the fabric must be woven by foot powered treadles machines. The weaver does his work, usually on a croft, and make a bit of money on these projects, but likely not enough to support himself in a comfortable manner.
Here is Donald Mackay working on his loom, working away in his small shed as he chatted with our group.
His prices:
The Butt of Lewis and its lighthouse: