On the Artificial Production of Minerals andPrecious 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 verifiable 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 remarkable 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. 



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