Mineralogical Notices. 225 
Art. XXVII.—Mineralogical Notices. No. I1.* 
On the Hardness of Minerals; by R. Franz, (Pogg. Ann., 
Ixxx, 37.)—This very important memoir relates to the compara- 
tive hardness of crystals on different surfaces, and in different 
directions on the same surface, and contains the results of numer- 
ous careful observations. 
Dorperire, a new species.—This mineral, of vegetable origin, 
occurs in Styria near Aussee, in peat. According to Doppler, 
(Wien Acad. Ber., Nov. Dec., 1849, 239,) and Haidinger, (ibid, 
287,) it is when fresh, brownish black with a dull brown streak 
and greasy subvitreous lustre, and also in thin plates which are 
reddish brown by transmitted light. G=1-089, according to Fot- 
terle. On exposure to the light, the substance becomes very elas- 
tic like caoutchouc. Heated to 100° C., when it loses 78°5 p. ¢. 
of water, it resembles a black pitch; on heating the fresh mineral 
with potash, ammonia is given off. Analysis afforded Schrotter, 
(Wien Acad. -Ber., 1849, 285,) 
fas 51 5:34 O 43:03 
giving the empirical formula C*H‘O*%. Schrotter considers it 
an unusually pure and homogeneous peaty substance from whose 
cellulose 2 parts of water are removed—C*H ‘07 losing 2HO be- 
comes C*H*O5, the formula above. . 
Magnesite.—Breithaupt (Pogg., 1xxx, 313,) found the angle of 
a magnesite from Snarum, Norway, 107° 284’. Scheerer ob- 
tained for the mineral on analysis— 
6 Mg Fe 
1. 51447 47-296 0°786 0-470 
2. 52°768 47-232 undetermined 
The formula from the first analysis is Mg 6. 
Nemalite of Hoboken, New Jersey.—Analysis by Rammels- 
berg, (P ogg. Ann., Ixxx, 284,) : 
Meg Fe st Si 
64:36 405 29°48 0°27=98°65 
Oxygen, 25-49 0-90 26:20 
This result, giving for the formula of Brucite, MgH, confirms 
the recent analyses of Whitney, (J. Bost. Nat. Hist., 1849, p. 36,) 
d Wurtz, (Dana’s Min., 3d. edit., p. 682.) 
Chlorite.—Delesse obtained (Ann. d. Mines, [4], xvi, 520) for 
a dull bluish green chlorite of feathery texture, from the Mandel- 
Stein porphyry of Oberstein, and of Planitz near Zwickan, the 
following composition :— 
1. Oberstein, 29-08 set me ss oe 
2. Planitz, 2945 1825 817 1512 045 1532 1257= 99°33 
Sen * For Notices, No. I, see preceding volume, p. 245. 
BOND Serres, Vol. XI, No. $2.—March, 1851. 29 
