Hones — 'Tests \ipon the Synthetic Sapphires of VcrneuU. 271 



Akt. H'XN 111.— Some Tests upon the Synthetic Sapphires of 

 Verneuil I by Alfred J. Mosks. 



Vkrneuil describes briefly"'^ synthetic sapphires of " beau- 

 tiful color" made in his oxyhydrog-en furnace by addine; to the 

 alumina "1-| per cent, of magnetic oxide of iron and J per 

 cent of titanic oxide." The resulting ovoids or cone-shaped 

 masses are said on authority of AVyrouboff to be "unique 

 crystals, uniaxial, negative, weakly doubly refracting and with, 

 consequently, the optical propei'ties of the natui-al sap])hire." 



An examination of material sent by L. Heller & Son con- 

 sisting of one dozen of the cut stones and one of the uncut cone- 

 shaped masses yielded some exact tignres which are here stated. 



Three analyses were made by my assistant, Dr. M . A. Lamme. 

 No. 1 — Ti'ansparent fragments of the uncut cone, not includ- 

 ing either the blackish scoria-like material at the apex or the 

 thin brownish layer at the base. No. 2 — Two small cut stones, 

 one deep blue, one pale blue in color. No. 3 — One deep blue 

 cut stone. 



12 3 



Weight Weight Weight 



0-4070 gin. 0-3990 gm. 0-2966 gm. 



A]„0, 99-84 99-85 99-83 



Fe^O^ trace trace trace 



TiOj -- 0-11 0-12 0-13 



SiO none none none 



99-95 99-97 99-96 



The material was crushed in a diamond (steel) mortar, through 

 a 100-mesh screen and all particles of steel removed by the 

 repeated use of a strong magnet. It was then fused with 

 KHSO^. The alumina obtained was re-fused for a colori- 

 metric determination of TiO„. 



There are few recorded analyses of true sapphire and I 

 believe none showing either chromium or titanium. The 

 coloring matter suggested by these analyses is iron. For 

 instance : 



Indiaf Ceylon:]; Ceylon:^ 



Al.O, -. 97-51 99-33 99-26 



Fe^Og 1-95 0-92 0-97 



SiO 0-80 



*Comptes Reiidus, Jan. 17. 1910. 



■f J. Lawrence Smith, this Journal (2). xi, 54, 1851. 



X Karl Pfeil, Centralblatt f. Min., 1902, p. 145. 



