APPENDIX 4. 

 GEM AND MINERAL NAMES. 1 



The following list of gem names has been compiled from the 

 literature and from correspondence with the producers of precious 

 stones in the United States. The list is in two parts. Part I gives 

 the name of the gem followed by the name of the mineral species 

 to which the gem belongs. Part II aims to give all the names of the 

 mineral species followed by the names of the corresponding gems. 



Many of the names have been coined by the dealers in particular 

 minerals for the evident purpose of increasing their sales. Many 

 people who buy cheap gem stones under fanciful names probably 

 would not buy the stones if they were offered under their true min- 

 eralogic names. The list herewith will enable those who are inter- 

 ested to look up the true mineral species of the gems offered. 



The use of the name of a valuable gem mineral combined with 

 another modifying word instead of the true name of a mineral of 

 less value — for example, "Alaska diamond" instead of quartz, or 

 "Arizona ruby" instead of garnet — is incorrect and should be 

 avoided. The list does not contain all the names applied to gem 

 minerals. Such self-evident names as "milky opal" and "blue 

 bend" are omitted. The object of the list is to show the mineral 

 species forming the gem and not to list all possible names which have 

 been used for gems. 



A few names of substances not minerals but commonly used as 

 gems have been included. Artificial products, however, many of 

 them made of glass and fraudulently sold under mineral names — for 

 example, glass sold as "fire agate" — have been excluded. 



PART 1.— GEM NAMES. 



A. 

 Achirite=dioptase from Siberia. 

 A chroite= colorless or white tourmaline. 



Actinolite=green iron, calcium, and magnesium silicate (amphibole). 

 Adamantine spar=hair-brown corundum. 

 Adelaide ruby=blood-red pyrope (garnet) from South Africa. 

 Adularia=orthoclase (feldspar). 

 Aeroides=pale sky-blue beryl. 



Agalmatolite= compact mica (aluminum and potassium hydrous silicate); also com- 

 pact pyrophyllite (aluminum hydrous silicate). 

 Agate = variegated chalcedony. 



i From Mineral Resources of the United States for 1917, by Dr. W. T. Sehaller, of the United States 

 Geological Survey and formerly custodian of gems and precious stones in the United States National 



Musemiim. 



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