On the Artificial Production of Minerals and Precious Stones. 129 
Having once first produced fluoride of aluminum and decom- 
posed it again under the influence of steam, hydrofluoric acid is 
formed and corundum is crystallized. 
By acting at the same time on the vitrifiable earth of the 
crucible, there is first produced some silicate of alumina, which 
by uniting itself with baryta, has produced the beautiful crystals 
of double silicate of aluminum and of barium which we have 
presented. 
Such is the theory we think rational; and it seems to result 
from our experiments that fluorides are not only excellent 
mineralizers in the mass, but that they can carry along with them 
the most fixed bodies. As a proof of this assertion one can instance 
that rernarkable formation of orthose felspar produced artificially 
in the upper part of a copper furnace at Mansfeld. The use of 
the fluoride of calcium in the bed of fusion, which produced that 
felspar, permits us to suppose that the fluorine served here as a 
transporting agent or vehicle. 
Thus, we are justified in expecting that, by prosecuting our 
studies, we may be able to produce crystals capable of application 
in jewellery and watchmaking. The last experiments have 
shown us that we are making good progress. We have already 
obtained cut crystals of remarkable value. We hope they will 
shortly be presented for inspection. 
