1895.) Mineralogy. 655 
New Minerals.—Igelstrom* describes several supposed new min- 
erals from Sjögrube, Gouv. Orebro, Sweden, which are either massive 
or so poorly crystallized that their symmetry could not be definitely 
determined. Their names and supposed compositions are as follows : 
Lamprostibian.—A qualitative analysis showed the presence of much 
Sb,O, and FeO, with smaller amounts of MnO, As,O,, PbO, “and 
other substances ;” from which the mineral is supposed to be an anti- 
monate of iron and manganese. 
Elfstorpite—A qualitative determination yielded much H,O, As,O, 
and MnO, with traces of CaO and MgO, hence the mineral is sup- 
posed to be a very hydrous arsenate of manganese. 
Chlorarsenian.—Anhydrous arsenate of manganese (from qualita- 
tive tests). 
Rhodoarsenian.—Analysis furnished the following formula: 
(10 RO As,O,)+10 (RO H,O) in which R—=Mn, Ca, and Mg. 
Basiliite.—(Mn,O,), Sb,0;+7 Mn,O,. 3 H,O. 
_ Sjégrufvite—2 (RO), As,O,+ Fe, O,. As,O,+6 H,O, in which R= 
Mn, Ca, and Pb. 
Doelter, The Characters of Gems.—Eight years ago Groth is- 
sued a very interesting popular introduction to the study of gems, in- 
tended for the general public and also in a special way to inform jew- 
elers of the delicate mineralogical methods which may be made use of 
by them for the determination of stones. Great stress was laid upon 
the optical method of investigation, and a special microscope was de- 
signed and constructed for the use of jewelers. Doelter’ has recently 
published a more pretentious work, and one of a somewhat more 
practical character. The book is essentially a manual and includes 
some 260 pages. It contains a great deal of matter and this is very 
well arranged. Doelter shows that in spite of the delicate nature of 
the optical methods, they can only rarely be applied on cut gems. 
The specific gravity test, particularly when heavy solutions are used, 
is the most delicate test, and also the one most easily applied. In ad- 
dition, the examination with the dichroscope, and chemical and hard- 
ness tests, are applied in some cases. The artificial reproduction of the 
different gems in the laboratory, and the technical methods of imitat- 
5 Zeitsch. f. Kryst., XXII, pp. 467-472 (1894). 
ê Grundriss der Edelsteinkunde, Engelmann, Leipzig, 1887. 
7 Edelsteinkunde, Bestimmung und Unterscheidung der Edelsteine und 
Schmucksteine, die kiinstliche Darstellung der Edelsteine, von Dr. C. Doelter. 
Veit & Comp., Leipzig, 1893. 
