: Dr. Genth’s Contributions to Mineralogy. 21 
: — a gray ; color pitch-black: opaque ; fracture un- 
nchoidal ; brittle- 
; B. B. it fuses with intumescence to a ew slightly magnetic 
glass. Dissolves easily in hydrochloric 
: The analyses gave the following vandis: 
x a B Contains oxygen. 
ilies, 6. 4 BERS 8217 3219 ° 1671 =1672 
Alumina, . 1199 1200 1200 561 Ug 
4 Sesquioxyd ofiron, . 6°30 639 6-34 190 §— 
* Oxyd of ir 10°55 10°55 2-34) 
d of minngunene; 051 not det. 051 O11 
Oxyd of a . 15°28 1545 15°87 2-99 
Oxyd of didymium, } ®79 phot tt nies tee we 
Magnesia, ; - 054 114 0°84 0°34 
BANA Sdn ij) cir BRS 931 914 2-60 
Soda, oe 1-00 1-00 0:25 
Potach, ae 0-18 018 0:03 
Writer, <--° 1:19 1-19 106 = 1-06 
. Allanite isin near Eckhardt’s Parhidce, Berks county, Pa.— 
Iu color, Las appearance and its blowpipe reactions, resembles _ 
| very much the allanite from Orange county. 
> H. S6. Sp. gr. (at 27° Cels. ) = 3825-3: 831. 
| The analyses gave the following results: 
' B Mean. Contains oxygen. 
Silica, 5 32.97 32°81 8289 17-07 0 
* Alumina, 12-40 1259 12-49 ved Se 
Sesquioxyd of i iron, 710 756 7:33 S30 Sys 
-_ ; 902 902 200) 
i Oxyd re manganese, 0-25 not det, 0°25 0:05 
a Oxyd of cerium, . 15°79 1556 1568 227 
al! a, z i : . a ‘ 
é Ory of didymium, 10 17 1002 1010 eee” 
Magnesia, 1-91 1-63 177 =: O61 
MN oo TSO 6°94 T12 © - 202 
eo. k 0:09 009 0-02 
Reveb = 5 ay 0-14 014 0°02 
“ater, : 2°49 249 - 221 = 221 
It is fon abundantly near Eckhardt’s Furnace, Berks County, 
| a a, associa’ with quartz, zircon, mica and titaniferous mag- 
- hetite, 
"6, AMtnit from Bethlehem, Northampton county, Pa.—Mas- 
sive; H.=5; Sp. grav. (at 16° Cels.) = 3-491; lustre resinous ; 
rar brownish black; streak gray ; opaaNe +: ‘fracture subcon- 
¢hoidal, 
B.B. it decrepitates slightly and fuses with intumescence to an 
iron black magnetic slag. Hydrochloric acid dissolves it readily. 
_ Occurs in a decomposed granite in flat pieces of not more than 
lalf an inch in thickness; their surfaces are covered with a crust 
iydrated hee gen of iron and cerium, etc., resulting from 
osition of the allanite by the action o atmospheric 
