Dr. Thomson’s Notice of some new Minerals. 191 
It is a double anhydrous aluminous silicate. It differs from 
fuller’s earth by containing 2 (Cal S) instead of 2 Aq. 
5. Gymnite.—To the fifth mineral species which I mean to 
notice at present I have given the name of Gymnite, because 
its locality is the bare hills west of Baltimore. I got the 
specimen in my collection from Mr. Alger of Boston, well 
known for his and Mr. Jackson’s excellent geological descrip- 
tion of Nova Scotia. 
The mineral was in amorphous pieces, having a very pale 
and dirty orange colour. It is translucent on the edges; the 
lustre is resinous. It is very tough and difficult to break : 
this makes it difficult to determine the hardness; but it is softer 
than felspar. The specific gravity is 2°2165. When held in 
the flame of a spirit-lamp it becomes dark brown: with soda 
it fuses into a white opake bead; with borax into a colourless 
bead ; with nitrate of cobalt it assumes a rose-red colour, 
Being subjected to analysis, its constituents were found to 
be 
Meats ls see ce sone nt MOT 
PIRONIEEIEY® oC ee eae te 36°00 
Writer =. 2°29 ONG vaee i ite ep 
Alumina with trace of iron .. 1°16 
Panie*, *. 9" Seeds 2 ON BO 
99°72 
It is therefore composed of silica, magnesia and water, and 
its constitution may be represented by the formula 2 (Mg S) 
+ Mg S? + 4 Aq. 
6. Baltimorite——For the next mineral species which I 
mean to notice I am also indebted to Mr. Alger. The speci- 
men was labelled Asbestus with chrome, and the locality Balti- 
more; on this account I have given the species the name of 
Baltimorite. 
The colour is grayish-green. The mineral is composed of 
longitudinal fibres, adhering to each other, and has a consi- 
derable resemblance to asbestus; the lustre is silky. The 
mineral is opake; but when very thin it is translucent on the 
edges. It is a very little softer than calcareous spar. It does 
not fuse before the blowpipe, but assumes a brown colour. 
With soda melts into an opake, and with borax into a trans- 
parent bead. Its constituents are 
a Si oe ees) orn 
Magnesia. ....... 34°70 
Protoxide of iron... . 10°05 
Pt ae ee ee a BT, 9) 
WU CE acc ete ov ous oe 7 2O'OD 
09°85 
