Artificial Production of Minerals. 309 
- By mingling the elements which correspond to the com- 
position recently given by M. Rammelsberg for the magnesian 
and ferromagnesian tourmalines, and adding to them an ex- 
cess of magnesia or lime to supply the silicium with oxygen, 
I have obtained, among crystals of quartz, very well-defined 
hexagonal prisms, which present all the exterior and chemi- 
cal characters of tourmaline. 
The chloride of aluminum may be employed in the same 
way as the chloride of silicium. When treated with lime at 
a red heat, it produces chloride of calcium and of alumina in 
crystals, which may be referred to the proper types of corun- 
dum, the hexagonal prism, and acute pyramids. 
The same reaction takes place with magnesia, and besides, 
in the latter case, a part of the reproduced alumina may be 
combined with the magnesia in excess, so as to produce 
spinelle, recognizable by the form of its crystals in regular 
octahedrons truncated on the angles. At the same time, 
it is a better plan, in order to obtain spinelle, to bring to- 
gether a mixture of chloride of aluminum and chloride of 
magnesium, and lime brought to a red heat. With the 
ehloride of zinc and aluminum, we produce the zinciferous 
spinelle, or gahnite. | 
The chloride of titanium brought over lime, along with the 
other crystals, afterwards examined, yields oxidized tita- 
nium, under the form of Brookite. 
The oxide of tin, obtained in a similar way, is in crystals 
of the same form as that which I had formerly produced by 
reaction on steam. Thus the form of a rectangular prism 
remains, for the oxide of titanium and for the oxide of tin, 
produced by decomposition of the chlorates of these metals, 
at temperatures at least between 300 and 900 degrees. 
By causing the perchloride of iron to react upon lime, I 
have obtained oligistic iron, both in the most distant specular 
crystals, like those of St Gothard, and in transparent hexa- 
gonal plates, presenting by refraction the red colour of the 
ruby. The perchloride of iron mingled with the chloride of 
zine yields, in the same conditions, a crystallized combina- 
tion analogous to Franklinite. 
.. Lastly, crystallized magnesia or periclase of the Somma, 
