I picked up a very similar cashmere coat at a thrift store a few weeks ago, with the same pick stitching, length and pocket style, though a lower button stance. It says 100% Mongolian Cashmere and was has a Frank Brothers label. Never heard of Frank bros., but I wouldn't be surprised if it were made by the same company as your coat. I think the "Cashmere Mink" is most likely a trade name, as kabert suggested. I wonder could a close-up of the fabric tell us more?