The Great Geyser lies to the north of this plain, its basin, 60 feet in diameter, is at the summit of a mound 20 feet in height, composed of silica, a mineral that the Geyser water holds in solution, and which from the constant overflowing of the water, deposits layers of beautiful enamel, which at the top is too hard to detach, although round the base soft and crumbly.
"A Girl's Ride in Iceland"
Ethel Brilliana Alec-Tweedie
But carbonic acid, silica, sulphurous acid, have no hydrogen in their composition; that property cannot therefore be connoted by the term, unless those substances are no longer to be considered acids.
"A System Of Logic, Ratiocinative And Inductive (Vol. 1 of 2)"
John Stuart Mill
The soil of the Champagne vineyards is chalk, with a mixture of silica and light clay, combined with a varying proportion of oxide of iron.
"Facts About Champagne and Other Sparkling Wines"
Henry Vizetelly