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A glassy colorless mineral occurring in rhombohedral crystals, sometimes used as a gem. It is a silicate of glucina, and receives its name from its deceptive similarity to quartz.

A complex hydrocarbon, C14H10, found in coal tar, and obtained as a white crystalline substance with a bluish fluorescence.

One of the prominent embedded crystals of a porphyry.

A white or pinkish crystalline substance, C6H5OH, produced by the destructive distillation of many organic bodies, as wood, coal, etc., and obtained from the heavy oil from coal tar.

A white or yellowish white crystalline substance, C20H14O4, formed by condensation of the anhydride of phthalic acid and phenol. Its solution in alkalies is brilliant red, but is decolorized by acids. This reaction, being very delicate, is used as an indicator.

uced artificially as a colorless oil which unites with acids, ketones, etc., to form well-crystallized compounds.

licate of aluminia, lime, and soda, a zeolitic mineral commonly occurring in complex twin crystals, often cruciform in shape; -- called also christianite.

A pearly crystalline substance obtained by the decomposition of phillyrin.

A glucoside extracted from Phillyrea as a bitter white crystalline substance. It is sometimes used as a febrifuge.

a silicate of aluminia, with magnesia, potash, and some fluorine. It is characteristic of crystalline limestone or dolomite and serpentine. See Mica.

A bitter white crystalline substance obtained by the decomposition of phlorizin, and formerly used to some extent as a substitute for quinine.

A bitter white crystalline glucoside extracted from the root bark of the apple, pear, cherry, plum, etc. [Formerly also written phloridzin.]

A sweet white crystalline substance, metameric with pyrogallol, and obtained by the decomposition of phloretin, and from certain gums, as catechu, kino, etc. It belongs to the class of phenols. [Called also phloroglucinol.]

A yellow crystalline substance having a peculiar unpleasant odor, resembling the quinones, and obtained from beechwood tar and coal tar, as also by the oxidation of xylidine; -- called also xyloquinone.

A yellow crystalline substance, having a geraniumlike odor, regarded as a complex derivative of acetone, and obtained from certain camphor compounds.

A rare mineral occurring in tetragonal crystals of a white, yellow, or grayish color and adamantine luster. It is a chlorocarbonate of lead.

t masses or sticks. (b) Pure normal phosphoric acid. -- Phosphoric acid (Chem.), a white crystalline substance, H3PO4, which is the most highly oxidized acid of phosphorus, and forms an important and extensive series of compounds, viz., the phosphates. -- Soluble phosphoric acid, Insoluble phosphoric acid (Agric. Che…

phosphorus (Chem.), an allotropic modification of phosphorus, obtained as a gray metallic crystalline substance, having very inert chemical properties. It is obtained by heating ordinary phosphorus in a closed vessel at a high temperature. -- Phosphorus disease (Med.), a disease common among workers in phosphorus, giv…

n. Their alkaline solutions are fluorescent. Phenol phthalein, a white or yellowish white crystalline substance made from phthalic acid and phenol. Its solution in alkalies is brilliant red, but is decolorized by acids, and as this reaction is exceedingly delicate it is used as an indicator.

ned by the oxidation of naphthalene and allied substances. Phthalic acid (Chem.), a white crystalline substance, C6H4.(CO2H)2, analogous to benzoic acid, and employed in the brilliant dyestuffs called the phthaleins.