STRONTIA. 
213 
Fig. 52. 
carbonate of strontia, containing only a very small admixture of carbonate of lime and oxide 
of iron. In the vicinity of the court-house, strontianite also occurs in fibrous masses, im¬ 
planted upon a dark blue calcareous spar. Some of these fibres are nearly two inches in 
length, and resemble certain varieties of arragonite. 
Various crystalline forms have also been noticed at this 
locality. Of these, Fig. 52, Fig. 53, and Fig. 54, are intro¬ 
duced from Prof. Shepard’s paper on the Strontianite of Scho¬ 
harie.* P on a 120° CK; a on a 120° O'; o on o 160°. 
Fig. 53 represents a compound form, commonly called a V 
crystal. “ The face of composition is apparently parallel with 
the vertical edges between c and c (Fig. 52). The individuals 
project beyond the face of composition only on one side ; but 
the composition is often represented in parallel laminae.” 
“ Another form is represented by Fig. 54, though the planes 
c c are rarely very distinct. They are an inch in length (in 
the direction of the edge between a and a), and nearly half an 
inch in thickness. Colour bluish or reddish grey ; translucent. 
The surface P is streaked parallel with its edge of combina¬ 
tion with o.” 
The Emmonsite of Dr. Thomson, is certainly nothing more 
than a mechanical mixture of carbonate of strontian and carbo¬ 
nate of lime. The composition is stated to be as follows : 
Carbonate,of strontia,... 82.69 
Carbonate of lime,... 12.50 
Peroxide of iron,. 1.00 
Zeolite,... 3.79f 
The remarks made in regard to the mixtures of sulphate of barytes and carbonate of lime 
(page 207), are equally applicable in this case. The chemical composition alone cannot be 
relied on as a ground of specific distinction. 
BARYSTRONTIANITE. 
[From its containing both baryta and strontia.] 
Barystrontianite. Clcaveland and Phillips. — Stromnite. Thomson and Shepard. — Appendix to Strontianite. 
Beudant. — Baryto-Carbonate of Strontia. 
Description. Colour greyish white, passing into yellowish white. It occurs massive, ra¬ 
diated, or composed of small plates or radii somewhat diverging. Lustre shining, inclining 
American Journal of Science, XXVII. 363. 
t lb. XXXI. 171. 
