Mineralogy. 1143 
low mineral occur which Damour has shown to belong to a new 
species. The grains have an easy cleavage, and in the polari- 
scope exhibit a cross and series of rings, such as would be given 
by a section of a uniaxial mineral. The hardness is that of apa- 
tite, the specific gravity 3.26. | 
Heated in a matrass it gives off water and becomes white and 
opaque. Thin splinters can be fused in the blowpipe flame. Mois- 
tened with nitrate of cobalt, a blue color is obtained. It is not 
attacked by acids. 
Composition : 
P.O, Al,O, CaO H, 
14.87 50.66 17.33 16.67 = 99.53 
The formula P,O, 5 Al,O, 3 CaO + 9 H,O is deduced. 
ihe name is taken from that of the province containing the 
principal diamond localities. 
ous or silky luster, and is white when pure. Hardness = 6. It 
ses with difficulty to a slightly magnetic scoria, gives reactions 
r Manganese, and is not dissolved by acids. pos 
As seen by the following analysis it is essentially a bisilicate of 
the protoxides of iron and manganese: | 
SiO, FeO MnO CaO 
48.25 28.17 12.08 5.86 3.22 = 97-58 
j 
According to Bertrand the optical properties are those of the 
amphiboles. The two cleavages make an angle like that of am- 
phibole, the form is monoclinic and the orientation of the axes 
is like that in the amphiboles. The composition is also psc 
t of an amphibole. Similar species have already — 
scribed under the names of silfbergite, dannemorite, — 
This mineral differs so slightly from these varieties of hornblen 
a new name does not seem to be necessary. 
excellent illus- 
ed from photo- 
1 
al Soc. Min. de France, 1884, VII, No. 6, p. 232- 
ol, 884. 
Iv, No. 3, P. 493, 1 
