26.
28.
Beryl (Butterworths Gem Books)
by John Sinkankas, Peter G. Read
ISBN: 9780408015431
List Price: $44.95
29.
Field Collecting Gemstones and Minerals
by Sinkankas, John, John Sinka...
ISBN: 9781635618396
List Price: $58.95
30.
Gem Cutting : A Lapidary's Manual, 2nd Edition
by Sinkankas, John
ISBN: 9781635616231
List Price: $25.95