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 47·9 Alumina 34·0 Oxide of Iron 2·4 Soda (Na{2}O) 5·1 Potash (K{2}O) ·9 Lime 9·5 Magnesia ·2 ----- 100·0 Von Waltershausen gives the following as the composition of two specimens of Labradorite from Etna:-- I. II. Silica 53·56 55·83 Alumina 25·82 25·31 Sesquioxide of Iron 3·41 3·64 Magnesia ·52 ·74 Lime 11·69 10·49 Soda 4·09 3·52 Potash ·54 ·83 Water ·95 -- ------ ------ 100·58 100·36 Specimens of Augite from Etna have been examined by Von Waltershausen and Rammelsberg, with the following results:-- _Greenish_ _From_ _From_ _Black._ _Black._ _Mascali._ _Monti Rossi._ Silica 47·63 51·70 49·69 47·38 Alumina 6·74 4·38 5·22 5·52 Protoxide of Iron 11·39 4·24 10·75 7·89 " Manganese ·21 -- -- ·10 Magnesia 12·90 21·11 14·74 15·29 Lime 20·87 18·02 18·44 19·10 Sesquioxide of Iron -- -- -- 3·85 Water ·28 ·49 ·51 ·43 ------ ----- ----- ----- 100·02 99·94 99·35 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 41·01 Protoxide of Iron 10·06 Magnesia 47·27 Alumina ·64 Oxide of Nickel ·20 Water 1·04 ------ 100·22