74 The American Naturalist. [January, 
transparent in thin splinters. Before the blowpipe it decrepitates, but 
does not fuse. On charcoal it gives the reactions for lead, antimony, 
arsenic, traces of manganese and water. It is probably a lead 
antimony arseniate resembling hedyphane. Anthocroite.—When the 
ore from the Jakobsberg braunite mine is treated with hydrochloric 
acid, there is left as a residue a violet’ sand composed of little grains of 
a mineral that occurs scattered throughout the ore as well as through- 
out all the minerals associated with the ore, and in veins cutting the 
surrounding limestone. The largest masses of the mineral are in a 
Magnese vesuvianite, and from this it can be obtained in a pure form. 
Lumps of the new mineral” consist of small transparent grains of a 
light amethyst color, and a hardness of 5-6. It is biaxial, with an 
optical angle (in air) of about 100°. Its analysis shows it to be a bi- 
silicate with the composition : 
SiO, MnO CaO MgO Al 10, Fe,0, K,O.Na,O 
51.6 3-4 23.3 13:5 6.8 
Michel-lévyite is the monoclinic form of one sulphate, of which 
barite is the orthorhombic form. It was discovered by Lacroix ® in 
the crystallized limestone of Templeton, Canada. It is a flaky, white 
substance, with three cleavages. These are assumed as the three pina- 
coids, giving 77°~78° as the value of 2. The plane of the optical 
axes is perpendicular to œ Pæ, and the value of the optical angle is 
nearly 90° The principal bisectrix probably coincides with the axis 
6. Specific gravity—=4. 39. Messelite is found in aggregates of 
colorless or brown tabular crystals in a clay slate at Messel, a station 
on the railroad between Darmstadt and Aschaffenberg, Hessen. The 
crystals ® are monoclinic, with an extinction of 20° on the clinopina- 
coid. Their average percentage composition corresponds to the 
formula (Ca Fe Mg), (PO,),+214H,O. Wiluite is the name given by 
Prendel™ to a variety of vesuvianite from Wilui, Russia. Its com- 
position is: 
SiO, TiO, ALO, CaO MgO Fe Q .FeQ MnO oo Loss 
38.39 1.09 13.07 35.92 5.83 4.25 we 37 -90 
Crystals cut parallel to a prismatic face show the ey structure 
in which the two constituent substances have different refractive in- 
dices. In sections parallel to the base the inner substances show a bi- ` 




n Tb., p. 36. 
18 Comptes Rendus, CVIII., 1889, p. 1126. 
19 Muthman: Zeits. f. Kryst., XVIL., 1889, p. 93. 
20 Ib., p. 94. 


