460 PROFESSOR HEDDLE ON 
GARRETT, in his examination of the American ores, found a magnetic and 
a non-magnetic “ chrome sand.” 
In his formulation of these he makes the 
Non-magnetic, . : : Fe Cr, 89 : 42., Fe Fe, 6 * 26, 
The Magnetic, ; : ; Fe Cr, Gi" 07a), Be Fe, 38 * 64, 
The imperfect determination of the state of oxidation of the iron prevents 
the Shetland sands being tabulated in the same manner as yet. They are 
evidently much poorer in chromium. 
All these analyses show that although the richest chrome ores are non- 
magnetic, valuable magnetic varieties, which may be said to shade off into 
chromiferous magnetites, exist ; and large deposits of magnetic iron sands should 
be examined, in the hope that they may prove to be more or less rich in 
chromium. Should that metal be found to be a constituent of the sand, it 
would be of greater advantage to the manufacturer or extractor, that the same 
should prove to be @ mixture; as ordinary chromite, however intractible, is 
markedly less so than this substance (which is apparently a compound) has 
proved to be. . 
CHROMITE. 
- 1. From the large quarry at Hagdale, Unst, Shetland. The sample taken 
was a very crystalline mass, almost in isolated octahedra; the crystals were 
separated from one another by flakes of foliated pennite. After careful pick- 
ing, small grains of translucent quartz were still visible, though none could be 
seen in the uncrushed mineral. 
It was associated rarely with emerald nickel, and contained imbedded specks 
of a bronzy mineral which resembled Pentlandite. Other associates are tale, 
aragonite, and Kammererite. 
On 1:001 grammes— 
Silica, d 7 ; 5 ; 4. Fol 
From Alumina, : : ‘ °04 
Sibi 
Protoxide of Iron, : : : : 17° Sls 19° 465 
Protoxide of Manganese, . . . *499 
Sesquioxide of Chromium, . ; : 44°555 
Lime, . . ; ; ; : ; 1° 286 
Alumina, . : : ‘ ; ; 23,741 
Silica, ; . : . , ; 11-088 
98 * 688 
