1883.] Crystallography of Miargyrite. 375 



Crystal 12. Fig. 11. 



c, o, a, to, 7r, g. 



A small crystal, with c large ; and zone [o, ir, g] striated, and 

 the planes o, it alternating a good deal. 



Crystal 13. Fig. 3. 



a, c, M, o, d, s, t. 



This crystal and several like it measured by me are some- 

 what large crystals with large c planes, and much striated rounded 

 planes d, s, t, terminating the ciwstals at both ends in sharp tri- 

 gonal wedges. The measurements obtained on these crystals (one 

 of which showed the plane k) were only of value in determining 

 the forms actually present. 



Crystal 14. 



a, d, e, s, t, X, a), x, to, (205) ?, (104), c, o, p, g. 



A good crystal still attached, with others, to a matrix of quartz, 

 closely resembling specimens from Braiinsdorff. It is however 

 accompanied by a label which gives the locality Wolfsberg. Owing 

 to its attachment to the matrix, but few zones could be measured, 

 and these only approximately. From the habit of the crystals on 

 the specimen it seems probable that the crystal A measured by 

 Miller was removed from this specimen. The zone [opg] is largely 

 but irregularly developed, whilst the zone [dest] seems almost 

 curved from the number of planes. Amongst these e and X are 

 largely developed. In the zone [ca] the plane o is alone large, 

 a and m form simply a notched edge bounding the plane d. The 

 following are the principal angles obtained. 



On a loose crystal of similar habit the following forms were 

 observed : 



a, d, s, t, to, x, m, o, p, g, r 121, 12 71 ?, 836 ? 



These three latter planes are fairly well developed. The angles 

 obtained were however not good, and I feel no great confidence in 

 the indices I have assigned to the two latter planes, as they had 

 not the certainty obtainable when they are deduced from the 



