Looking at these rocks I thought mica, but under the lens I'm not so sure. The crystals do not have a bookish appearance. They seem clear with a flat reflective face. Any opinions. HCL has no effect.
Looks to be a fine graining of mica and quartz mixed. A very friable material you should be able to knock some loose on a piece of white paper and see the individual crystals better or pick it apart carefully and separate the crystals. The mica looks to be very thin and is disbursed between the quartz granules in my view.