FUSIBILITY.
- Readily fusible to a bead.
- With difficulty fusible to a bead.
- Readily fusible on the edges.
- With difficulty fusible on the edges.
- Infusible.
- a. Afford a fluid bead with carbonate of soda.
- b. Afford a fluid bead with but little of that salt, but with a larger quantity a slaggy mass.
- c. Afford a slaggy mass only.
This classification of minerals, according to their fusibility and their behavior with carbonate of soda, was originally proposed by Berzelius, and a table of the principal oxidized minerals arranged according to these characters is given in his handbook of the blowpipe, and thence adopted, with some alterations by Plattner, in the very excellent and detailed work already many times cited. In the following general table I., the more important silicates only are included, and in table II. are enumerated in alphabetical order those which afford characteristic reactions.
TABLE I.
Anhydrous Silicates.
Fus. alone and with NaC.
| Mineral. | Formula. | ||
|---|---|---|---|
| I. | |||
| a. | Axinite | . . ... ... ... ... ... ... ... (CaMg)3 ( B Si )3 + ( Al Fe Mn)2( Si B ) | Int. |
| Elaolite | . . ... ... ... (KNa)3Si + 3 Al Si | Int. | |
| Garnet | . ... . ... R3Si + R Si | ||
| Oligoclase | . ... ... ... NaSi + Al Si2 | ||
| Scapolite | . . ... ... ... (CaNa)3Si2 + 2 Al Si | Int. | |
| Spodumene | . . ... ... ... (LiNa)3Si2 + 4 AlSi2Int. | ||
| b. | Asbestos to II. | As Hornblende | |
| Augite some var. | . . . . ... (CaMgFeMn)3Si2 | Int. | |
| Epidote to III. | . ... ... ... ... ... (CaFe)3Si + 2( Al Fe Mn )Si | Int. | |
| Hornblende some var. | . . . ... ... (CaMgFe)4 + ( Si Al )3 | Int. | |
| Sodalite to III. | . ... ... ... Na3Si + 3 Al Si + NaCl | Int. | |
| Vesuvian | . . ... ... ... ... 3(CaMg)3Si + 2( Al Fe )Si | Int. | |
| c. | Biaxial Mica to III. | . ... ... ... ... K Si + 4( Al Fe )Si | |
| Hauyne | . . ... ... ... . ... (KNa)3Si + 3 Al Si + NaSi | ||
| Tourmaline to V. | . ... ... ... (R R B )4 Si3 | Int. | |
| II. | |||
| a. | Labradorite | . . . ... ... ... ... (CaNaK)Si + ( Al Fe) Si | |
| Lepidolite | ... ... ... (KNaL)F + (Al Fe) Si2? | ||
| Ryacolite | . ... ... ... K Si + Al Si2 | ||
| Albite | . ... ... ... NaSi + Al Si3 | ||
| b. | Augite some var. | . ... R3Si2 | |
| Actinolite | . . . ... (CaMgFe)4Si3 | Int | |
| Diopside | . . ... (CaMg)3Si2 | ||
| Humboltilite | . . . . ... ... ... ... 2(CaMgNaK)Si + ( Al Fe )Si | ||
| Sahlite | As Augite | ||
| Tremolite | . . ... (CaMg)4Si3 | ||
| c. | Pyrope | . . . ... ... ... ... (CaMgFe)3Si + Al Si + mCr? | |
| III. | |||
| a. | Anorthite | . . . . ... ... ... ... (CaMgNaK)3Si + 3( Al Fe )Si | |
| Nepheline | . . . ... ... ... (NaKCa)2Si + 2 Al Si | ||
| Obsidian | ... ... ... . . . . Si, Al, Fe, Fe, CaNaK | Int. | |
| Orthoclase | . . ... ... ... (KNa)Si + Al Si3 | ||
| Petalite | . . ... ... ... (LiNa)3Si4 + 4 Al Si4 | ||
| Pumice | ... ... . . . . Si, Al, Ca, K, Na, H | Int. | |
| b. | Gadolinite to V. | . . . . . ... (YCeLaFeCa)3Si | |
| Nephrite | . . . ... (CaMgFe)4Si3? | Int. | |
| Wollastonite | . ... Ca3Si2 | ||
| c. | Iolite | . . ... ... ... (MgFe)3Si2 + 3 Al Si | |
| IV. | |||
| a. | Beryl | ... ... ... ... Be Si2 + Al Si2 | |
| b. | Diallage | . . . ... ... (CaMgFe)3( Si Al)2 | |
| Hypersthene | . . ... (MgFe)3Si2 | ||
| c. | Fuchsite | . ... ... ... ... (K5Si )2 + 9( Al Cr)6Si6 | |
| V. | |||
| a. | Leucite | . ... ... ... K3Si2 + Al Si2 | |
| b. | Chondrodite | . . ... (Mg, MgF)4( SiSiF3) | |
| Olivine | . . . ... (MgFeCa)2Si | ||
| c. | Andalusite | ... ... ... ( Al Fe)3Si2 | |
| Chrysoberyl | ... ... Be + Al | ||
| Kaynite | ... ... Al3Si2 | ||
| Pycnite Topaz | ... ... ... 6Al 3Si2 + (3 AlF3 + 2SiF3) | ||
| Zircon | ... ... Zr Si | ||
| Staurolite | ... ... ... (Al Fe)2 Si | ||
Hydrous Silicates.
Fus. alone and with NaC.