510 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
10. The blue-black coloured variety afforded— 

Silica, : ; : 7. ols 306 
Alumina, . F 3 Bere alts) 
Ferric Oxide, . ; . Pa S95; 
Ferrous Oxide, . : ;  fe668 
Manganous Oxide, . ; * 487 
Lime, ; ; : . Uhl 
Magnesia, . : : fy Qing? 
Potash, - =.. ; 2 5h, oe LOG 
Soda, E , ; : °463 
Water, .. : : pay So 175) 
99 - 652 
Possible impurity, calcite. 

Magnesia, Lime, Iron,—Aluminous Amphiboles. 
Pargasite. 
vit) p10.8 
11. This variety was found among the heaps thrown out in some searchings 
after copper on Mount Errins; the pits are some three miles west of Urin or 
Errins, north of Tarbet in Kantyre. : 
The mineral was of characteristic appearance. It formed a bristly or hackly 
mass of parallel acicular crystals, of half an inch in length; these crystals stood 
erectly transverse to the surfaces of small veins in the rock. ‘This rock, which - 
lies in the district of chlorite schist, is here chiefly a vitrified-looking gneiss, 
not unlike a Cornish elvan ; but it is not unfrequently a foliated and beautifully 
plicated hornblende rock, with a subfibrous structure. 
The traces of copper consisted of chalcopyrite, in pyrite; there being also 
rarely crystals of quartz, felspar, and calcite. A pale-green mineral, which 
occurred in mammillated crusts, and much resembled pennine or grastite, was 
also not infrequent. Magnetite, pseudo after cubical pyrite, was rarely seen. 
Dolomite is also rare. 
This variety of amphibole, which, solely from chemical resemblance, I have 
classed under pargasite, was in translucent, hard, and brittle acicular crystals; 
these were of a fine rich green colour, and sometimes coated with the mammil 
lated green mineral. 
z 

