This book been around for 20 years... For those that are proficient in American:
" How To Be A Jewelry Detective"
A small and inexpensive book shows things of value to us ring collectors..
Shows all kinds of markings including some continental old silver like Fahrner and Jensen.. Also tells about manufacture. Old 'gem' settings,,Testing various silver contents,,Testing different types of 'gems'.. Also shows 19th and early 20th century stone cuts to include 'old European' cuts.
Fittings and findings..Testing for real enamel with both a neat 'home made' device and shows a cool batt operated enamel tool that would be great at shows for those a bit timid with a riker pin and lighter!
- again, a great read for a small price.