Regarding the gemstone books, I wouldn’t call the Arem books the
best. it’s been a while since i’ve seen them, but as I recall
they have lots of info and lots of great pictures. I saw some
material on synthetics that was very detailed, too. But, as
gemology ID books they are not the best. For detail and the last
word I like Gems: Their Sources, Description and Identification,
by Webster. There is a new edition revised by Peter G. Read,
also a great author on gems, so the revision should be top notch.
List about $125, try IGI, who will have it cheaper. Maitlins’
book the best easy book on gem ID. Liddicoat also very very good,
more detail, a bit more advanced. HTH.