TY  - BOOK
AU  - Webster, Robert
TI  - Gems: : Their sources, descriptions and identification 
PY  - 1962///
CY  - London: 
PB  - Butterworths & Co. (Publishers) Ltd., 
KW  - Chemical technology
KW  - Gemstones
N1  - Vol. 1 (xii, 1p.-464p.)
Vol. 2 (vii, 465p.-792p.)
ER  -