RARE Sterling Silver napkin rings Scottish semi- precious stones amathyst boxed

Excellent condition in their original box. Box is in excellent condition, note the little bit of wear inside on the silk where the hinge is. Napikn rings are splendid, scottish theme one has a well cut Amathyst the other another stone, perhaps citrine or caingorm. With the scottish them perhaps caingorm? Condition is excellent clean hallmarks for Birmingham 1927. Makers mark is JC & S which I believe is Joseph Cook & Son. Could benefit from a polish. Silver weight 40g (includes stones). Comes with a valuation from 1980, interesting they are describing the stone as a Citrine.