TY  - BOOK
AU  - Hurlbut Cornelius S
AU  -  Switzer George S
TI  - Gemology
U1  - H19, L9 
PY  - 1979///
CY  - New York    
PB  -  John Wiley and Sons     
KW  -  Gem stone
KW  - Geology
ER  -