I keep finding samples of this rock - which I believe is quartzite because it's hard and crystaline (always fractures along facets)
My guess is that the rock was sedimentary to begin with.
Many samples I find have back spherical things in them about 1 cm in size.
There is some small indication of radial spikes and some appear to have a halo around the perimeter.
If they are fossils and not simply geological they might be Ediacaran.
These are being found along the shore of the British Columbia mainland north of Vancouver.IMG_0968.CR2 of British Columbia mainland just north of Vancouver, B.C.