Gotta say they look an awful lot like Tam O Shanter stones.
VINTAGE DARK GREEN CHARNLEY FOREST SHARPENING STONE!!! | eBay
VINTAGE LIGHT GREEN CHARNLEY FOREST SHARPENING STONE!!! | eBay
Maybe they could be Lynn Idwals, but I really don't think they are CF's. Though identifying CF can be a guessing game quite often.