~ 1892.] Mineralogy and Petrography. 701 
and 2 E x, for celestite is 87° 40’ 20”.——-Miigge™ has made an inter- 
esting study of quartz crystals imbedded in eruptive rocks. These 
were isolated by treatment of thin slices of the rocks with HF, and 
the etched figures produced upon them by the reagent were investi- 
gated. Of 888 individuals examined 382 were found to be simple, 506 
twins of either right or left handed crystals, and 12 twins of right and 
left crystals. Pyrogenous quartzes like those deposited from solution 
are thus found to be more common in twinned than in simple forms. 
Lacroix” contributes a few notes on French minerals, especially 
those from the Central Plateau. He finds /eucite forming veins in the 
basalt of Mt. Doré, with peripheral bands of feldspar. Christianite 
crystals imbedded in calcite occur in calcified inclusions in a basalt 
dyke at Montaudoux, Puy-de-Dém. The same mineral is in the sani- 
dinite bombs of Monac, and is associated with chabasite at Araules in 
the Haute-Loire. Mesotype, analeite, zircon, sphene, vivianite, molyb- 
denite, kermesite and pyrite are the other minerals mentioned in the 
article Schrauf describes the metacinnabarite crystals of Idria, 
Auer and discusses their origin as well as that of the associated mer- 
cury and cinnabar. The crystals have a density of 7.66. They form 
the outer coating of spherules that within are massive metacinnaba- 
rite. Their crystallization is regular and habit dodecahedral. 
Pearce" calls attention to the existence of tellurium and bismuth in 
nearly all the sulphides of the Leadville region. Hills recently 
exhibited to the Colorado Scientific Society pseudomorphs of malachite 
after azurite on which are implanted crystals of a second generation 
of the last named mineral with the same orientation as the original 
azurite. Lacroix and Baret” find bertrandite at Mercerie in the 
Commune of La Chapelle-sur-Erdre, France. Its crystals are elon- 
gated parallel to the base, and are associated with orthoclase, albite, 
quartz and apatite in a granite—-—The supposed sulph-antimonite of 
nickel, korynite, from Siegen, according to an analysis made by. 
- peyres and Busz,” is a normal ullmanite, whose composition is : 
MNeues. Jahrb. f. Min., etc., 1892, i, p. 1. 
Bull. Soc. Franç. d. Min., xiv, p. 318. 
Jahrb. d. k. k. geol. Reichsanst., 1891, xli, p. 349. 
Proc. Col. Sci. Soc. 1890, iii, p. 257. 
18Ib., p. 258. 
Bull. Soc. Franç. d. Min., xiv, p. 189. 
%Zeits. f. Kryst., xix, 1891, p. 8. 
