Fam. 5. Salt-SilexTopaz.
6. Inflammable-SilexDiamond.
7. Ore-SilexGarnet.

535. Still all the silicious minerals are not exhausted with these combinations. But now the silicious earth can combine with nothing more than the elements, whence three families originate.

Fam. 8. Water-SilexHornstone, Silicious schist, Jasper, Flint, Opal.
9. Air-SilexSilicious sinter, as Tripoli and Polierschiefer.
10. Fire-SilexObsidian with Pitchstone, Pearlstone and Pumice.

536. Upon casting a glance at this series, it is shown, that the first seven families occur in a crystalline, but the last three only in a compact or structureless condition. The latter occur at the same time in large masses, the former, on the contrary, but scantily dispersed. The first family or the quartz, occurs as well in a compact and massive state as crystallized; the others, on the contrary, taken collectively, are only crystallized, and scarcely form small rocks here and there, but never mountain-chains. They are the precious stones proper, both on account of their hardness, as also their rarity. Precious stones are thus only combinations of silex with other earths, and with the classes; on the contrary, the elemental silices only, viz. the earth-, water-, air-and fire-silices, are massive.

537. It is here shown, that freedom finds a place also in dead nature. Quartz only is necessary as the earth in general. Its marriages with the other earths, &c., to form precious stones are not necessary, but free or accidental, and may therefore happen for the first time in the laboratory.

538. If we now proceed to the arrangement of the Clay, we find exactly the same law to prevail in the genesis of its minerals i. e. stöchiometric combinations with other orders, classes, and elements. We have likewise—

A.—Earth-Clays.
Fam. 1. Silicious claysFelspar.
2. Argillaceous claysSapphire.
3. Talcose claysRuby.
4. Calcareous claysEpidote.
B.—Class-Clays.
5. Salt-claysSchorl.
6. Inflammable claysAzurite.
7. Ore-claysHarmotome.
C.—Elemental-Clays.
8. Water-claysClay-slate.
9. Air-claysPotter's-clay, Clay-stone.
10. Fire-claysLavas, Phonolite, Toad-stone.

The water-clays are hydrates; the air-clays volatilized hydrates; the fire-clays are clay fused or transmuted by heat. Here also the first 7 families only are crystallized; the 3 last, on the contrary, as well as the first in part, occur only in a compact state and in large masses.

539. The Talcs follow the same laws, and we have—

A.—Earth-Talcs.
Fam. 1.Silicious talcsMica.
2.Argillaceous talcsSapphirine.
3.Talcose talcs Talc, Chlorite.
4.Calcareous talcsAugite.
B.—Class-Talcs.
5.Salt-talcsHornblende.
6.Inflammable-talcsAsbestus.
7.Ore-talcsOlivine.
C.—Elemental-Talcs.
Fam. 8.Water-talcsSerpentin, Steatite.
9.Air-talcsLithomarge, Fuller's-earth, Bole.
10.Fire-talcsBasalt.