276 . The American Naturalist. {March, 
Nordmark 1.0915: 1: .5848 7 = 74°38'59” 
Zillerthal (colorless) 1.0922 : 1: 5887 8 = 74°16/28" 
Arany-Berg (yellow) 1.0945 : 1: .5918 6 = 74°19'38” 
Arany-Berg (black)........... ..... anO Ts 6876. P = TA° 4687 
The optical angle for the Nordmark crystals is 2Vna = 60°44’, and 
C/\e¢ = 45°21’. For the dark Zillerthal diopside 2Vna = 58°56’ 
and C/\c = 34°4. 
Herderite from Hebron, Maine.—A single specimen of Her- 
derite from Hebron, Maine, is described by Wells and Penfield” as a 
few yellowish white crystals on albite. The crystals have a tabular 
habit, with oP, æ P, 3P and £P the only forms observed. The density 
is 2.975 and composition : 
P,O, BeO CaO (by diff) H,O F Insol. Total 
40.81-15.32 32.54 5.83 .40 5.27 = 100.17 
Corresponding to Ca Be (OH) PO, or aherderite in which nearly all 
of the fluorine is replaced by hydroxy]. 
Mineralogical Notes—A calcium carbonate of secondary origin. 
from the Marble Mountains of Wolmsdorf in Glatz has been analyzed , 
by Kosmann” with the following astounding result: Ca CO, = 4.32; 
chemically combined H,O = 1.54; mechanically combined H,O = 
94.13. The author believes the mineral to be a hydrated carbonate 
CaCO, + 2H,0 capable of absorbing a large quantity of water, simi- 
lar to the ‘ Mountain Milk’ of Rose. 
The friedelite of the Manganese mine of Sjogrube, Orebro, Sweden, 
occurs in large quantity in clefts, veins, etc., that are partially filled | 
with calcite. An analysis yielded Igelström :” 
SiO, Cl MnO FeO CaO MgO NaO H,O Total 
34.36 3.00 45.88 1.35 150 150 2.79 9,00 = 99.38 
On the Azurite from the Laurion Mts., Greece, Zimanyi” has found 
28 forms, three of which (?Pa, $Pæ and $Pæ ) are new. The crys- 
tals have the usual habit of the mineral, and they compare favorably 
in beauty with those from Chessy, Arizona and Utah. 
Amer, Jour. Sci., xliv, 1892, p. 114. | 
WZeits. d. deutsch. geol. Ges., xliv, 1892, p. 155. 
*Zeits. f. Kryst., xxi, p. 92. 
“Ib. xxi, p- 86. 
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