1890.] Mineralogy and Petrography. 73 
hardness is 3-3.5. In composition it corresponds to annadergite, with 
one-third of the nickel replaced by calcium (24NiO, % CaO), As,O,+ 
8H,O. [NiO=25.01, CoO=.76, CaO=p9. 32, As,O.—=39.33, H,O— 
25.01 |.—Hydroplumbite and Plumbonacrite.—The former mineral is in 
very small scaly crystals, with a pearly lustre, forming thin flakes of a pure 
white color, covering all the lead minerals of aspecimen of associated 
lead ores, that probably came from Leadhills, Scotland. The amount of 
the new mineral obtained was too small for analysis; but from the 
synthesis of a similar substance, Heddle ™ infers that its composition is 
3PbOH,O. The second mineral (from Wanlockhead) resembles 
hydroplumbite in appearance, but yields upon analysis a result corres- 
ponding to the formula PbCO,+ 3 PbO H,O [PbO=92.85, CO,==4.76, 
H,O=2.01, residue=. 78]. Fiinkite is described by Hamberg"™ from 
Piba, Sweden. It occurs in greenish-brown tabular orthorhombic 
crystals, with a hardness of 4.5, and Sp. Gr =3.87. Its composition 
is: 

As,O, ShO, mods Fe,O, geo’ CaO MgO H,O 
29.1 2-5 LS 35-38 +4 1.7 9-9 
——Fouguéite—In his excellent paper on scapolite rocks, Lacroix ® 
describes a dimorphous form of zoisite occurring as a constituent in 
an anorthite gneiss from the District of Salem, Madras, India. The 
new mineral is found in corroded and rounded monoclinic crystals, 
elongated in the direction of their ¢ axes, and polysynthetically 
twined with the orthopinacoid as the composition face of the various 
lamellez. They possess a well-marked cleavage parallel to the face as- 
sumed as the basal plane, which makes an angle of 108° with « Pæ. 
The plane of their optical axes is oP, and the optical angle 2\/ is 
about 90°, with å as the positive acute bisectrix. The pleochroism is 
weak in yellow tints. The mineral is infusible before the blowpipe, 
and has a specific gravity of 3.24-3.31. It occurs in two varieties, 
the compositions of which are as follows : 
SiO, Al,O, FeO CaO: Eos. 
Colorless: 36.6 32:5 Io >. 3490 2.7 
Yellow: ee 31-9 4.4 23.5 2.7 
Pleonektite occurs pleite in the gangue of the manganese 
mine, Sjégrufvan, OM ee Parish, Örebro, Sweden. It is a light 
gray mineral,'® with a hardness of 4, and a metallic fatty lustre. It is 
13 Ib., p. 201 
14 Geol. För. Förh., XI., 1889, p. 212. 
15 Bull. Soc. Franç de Min., 1889, p. 327. 
16 Ingelström : Neues Jahrb. f. Min., etc., 1889, IL., p. 40. 

