Mineralogy and Geology. 119 
These results agree so closely with the foregoing from différe 
specimens in a distinct matrix, that there can be no doubt they all 
no toa definite mineral whose composition is constant in its 
ing physical conditions. The percentages correspond remark- 
abl well with those calculated from the formula to which they 
lead. The results placed —— as found, are those of the analysis 
Il =~ given, after deducting the amount of CaO SO,, 2HO, 
equal to the SO, obtained, which is much greater in this “than in 
the preceding analyses whose numbers are so obviously similar, 
that deduction in all is quite superfluous. 
Calculated. Found. 
SHO = 11°43 11°84 
. 40a0 = 112 8-44 28°69 
2310. = «61°62 15°65 15°25 
5BO; = 175-20 44-48 44:2 
393°82 100-00 100-00 
Of the various modes in which the constituents of the mineral 
may be arranged, I prefer the following, and therefore using the 
notation so far employed in mineralogy, propose the formula, 
2CaO0SiO,+2(CaO 2BO,, HO)-+-BO,, 3HO, 
as that of the —_ mineral, to which I give the name Silicoboro- 
difference 9 or composition between mine ound in 
in the sam t i 
be mentioned, being sanaig indicated by these terms; the formula 
of the atte. according to my ownresults, when include 
some identical grouping, is * 
NaO 2BO,, 10HO-+2(CaO BO,, HO)+BO,, 3HO. 
For comparison dake’ I add the formula of cryptomorphite, the 
other borate found in gypsum here, also rewritten on the same plan 
as the preceding, 
The constituents of silicoborocalcite are 
a of datholite, the only other known hydrated silicated borate 
for 
This expression shih egies ve ser uaiike e those shown above 
In datholite, as in all silicated borates, 
the boracic acid is sometimes held to be basic, <a Min., 4th ed. 
. 
