Rubies and sapphires

Author:	Aitkens, Irene.
Year:	1931
Document Type:	USBI
Issuing Agency:	Dept. of Commerce, United States Bureau of Mines,
SUDOC:	C 22.11:6471
Series:	Information circular /Department of Commerce, United States Bureau of Mines ;
Report Number:	6471
Subjects:	Sapphires
	Precious stones
	Rubies
Link:	https://hdl.handle.net/2027/mdp.39015077576513