Hydrofluoric Acid (Fluorohydric Acid).--This acid is used to form some of the most volatile and sensitive compounds employed in the Daguerreotype. It is one of the most dangerous bodies to experiment with: it is volatile and corrosive, giving off dense white fumes in the air. It combines with water with great heat. At 32 deg. it condenses into a colorless fluid, with a density 1.069. It is obtained from decomposition of fluorspar by strong sulphuric acid. It readily dissolves the silica in glass, and consequently cannot be kept in a vessel of that material. It is prepared and kept in lead.英文原著 · 《American Hand Book of the Daguerreotype》
He looked down to it, and rubbed the ache out of the back of his neck. All about him the fresh morning was falling; yonder shone a green-mottled face of granite, and there a red iron blow-out streaked with veins of glittering silicate, and in this corner, still misted with the last delicate shades of night, glimmered rhyolite, lavender-pink. The single-jack dropped from the hand of Gregg, and his frown relaxed.英文原著 · 《The Seventh Man》
Helena. Shelly matter deposited by the waves. Siau, M., on ripples. Signal Post Hill. Silica, deposited by steam. -large proportion of, in obsidian. -specific gravity of. Siliceous sinter.英文原著 · 《Volcanic Islands》