Elie de Beaumont affirms that the lavas of Etna consist of labradorite, pyroxene (augite), peridot (olivine), and titaniferous iron. Rose was the first to prove that the lavas of Etna do not contain ordinary felspar (or potash felspar), but labradorite (or lime felspar.) (Annales des Mines, 3 serie, t. viii., p. 3.) Elie de Beaumont detached a quantity of white crystals from the interior of a lava found between Giarre and Aci Reale; these were analysed by M. Auguste Laurent with the following results in 100 parts:—

Silica
Alumina
Oxide of Iron
Soda (Na2O)
Potash (K2O)
Lime
Magnesia
 47·9
34·0
2·4
5·1
·9
9·5
·2
100·0

Von Waltershausen gives the following as the composition of two specimens of Labradorite from Etna:—

Silica
Alumina
Sesquioxide of Iron
Magnesia
Lime
Soda
Potash
Water 		I.
53·56
25·82
3·41
·52
11·69
4·09
·54
·95
100·58 		II.
55·83
25·31
3·64
·74
10·49
3·52
·83
—
100·36

Specimens of Augite from Etna have been examined by Von Waltershausen and Rammelsberg, with the following results:—


Silica
Alumina
Protoxide of Iron
,, Manganese
Magnesia
Lime
Sesquioxide of Iron
Water

Black.
47·63
6·74
11·39
·21
12·90
20·87
—
·28
100·02 		Greenish
Black.
51·70
4·38
4·24
—
21·11
18·02
—
·49
99·94 		From
Mascali.
49·69
5·22
10·75
—
14·74
18·44
—
·51
99·35 		From
Monti Rossi.
47·38
5·52
7·89
·10
15·29
19·10
3·85
·43
99·56

Olivine is generally met with in the lavas of Etna. It has an olive, or bottle-glass green colour, and is disseminated through the lavas in the form of small crystalline grains, sometimes of some magnitude. Specific gravity 3·334. A specimen from Etna gave the following results on analysis:—

Silica
Protoxide of Iron
Magnesia
Alumina
Oxide of Nickel
Water
 41·01
10·06
47·27
·64
·20
1·04
100·22

The titaniferous iron of Etna is found disseminated through the mass of the lavas, and is plainly distinguished when a thin section is examined under the microscope. It is sometimes met with in masses. A specimen from Etna, analysed by Von Waltershausen, was found to contain:—