500 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
Craigie the colour was somewhat bronzy—indeed, the finders were guided to 
the quarry at the latter locality by flashes of light reflected from what looked 
like bronzy buttons, on a road which had been metalled from the quarry. At 
both localities the lustrous foliations were stippled with dark green duller por- 
tions, consisting of ordinary serpentine. These portions apparently presented 
the section of former crystals of augite, which had pierced at right angles the 
less-changed, lustrous and foliated mineral. 
If these truly serpentinous pseudomorphs be after augite, it is probable that 
the still lustrous portions represent diaclasite,* to which they bear a strong 
resemblance. So closely packed were the dull pseudomorphs in the general — 
mass, that it was vain to attempt absolutely to separate them, but the green 
glimmering portions were as far as possible selected. 
The specific gravity of the Black Dog mineral was 2 - 649. 
On 1 - 092 grammes— 
Silica, : : *407 
From Alumina, . “0a 
elle = 38° 186 
Alumina, : ; ‘ DUNS 
Sesquioxide of Chromium, - 276 
Ferric Oxide, . : ; °028 
Ferrous Oxide, > a 8-479 
Manganous Oxide, . "513 
Lime, ’ : : ; Bene 
Magnesia, : ; . 32°418 
Potash; ‘ en 1°401 
Soda, é : : ‘ °065 
Water, . ; ; OAS 

100° 486 
Insoluble silica, 5 - 914 per cent. 
In one—the more southerly—of the quarries where this mineral occurs, at 
Craigie, it is associated with arborescent filaments of pyrite, of a gold-yellow _ 
colour. Gold is said to have been found here ! 
* SrrenG considers Schiller spar as altered bronzite (enstatite) ; Dscrorzpaux, however, finds 
that it has a negative bisectrix, which makes it altered diaclasite. In the lustrous portion there is 
really no apparent alteration ; and the hardness, gravity, and colour are all nearer diaclasite. 

