THE 
LONDON AND EDINBURGH 
PHILOSOPHICAL MAGAZINE 
AND 
JOURNAL OF SCIENCE. 
[THIRD SERIES.] 
JUNE 1840. 
LX VI. On crystallized Native Oxalate of Lime. By H. J. 
Brooke, Esq.^ 
I HAVE had in my possession for some months a specimen 
of calcitef in compound crystals of the metastatic form of 
Haliy, from i to | of an inch long, with irregular and curved 
surfaces occasioned by the intersections of the numerous indivi- 
duals of which the crystals are severally composed, and which 
stand on a rather soft light gray matrix. It is uncertain from 
whence the specimen was brought, but Mr. Heuland sup- 
poses it to have come from Hungary. 
On the crystals of calcite are deposited a few small crystals, 
from loiig? of oxalate of lime, which had 
from their high lustre been supposed to be some ore of lead. 
It was, however, apparent that they differed in form from all 
the known lead ores, and on examination by Mr. Sandall at 
Mr. R. Phillips’s laboratory, they were found to be oxalate 
of lime with one proportional of water. 
The crystals appear to have been formed contemporaneously 
wHth those of the calcite, in which some of them are partly 
imbedded, a circumstance which excludes the supposition of 
their being of vegetable origin ; and as only one other oxalate, 
that of iron, is known to exist in the mineral state, and as 
it occurs in a bed of wood coal, and the oxalic acid contained 
in it may be presumed to have been derived from vegetable 
matter, this oxalate of lime will afford the first instance of 
the occurrence of oxalic acid as a distinct mineral product. 
The primary form of the crystals is an oblique rhombic 
prism, fig. 1. P on M measuring 103° 14' and M on M/ 
100° 36' : a cleavage parallel to P has induced me to adopt 
* Communicated by the Author. 
t In a list of minerals published a few years since, I proposed this name 
for the common rhombohedral carbonate of lime ; calcite and aragonite 
thus denoting the two varieties of this substance. 
Phil. Mag. S. 3. Vol. 16, No. 105. Jane 1840. 2 H 
