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A grayish or dark green mineral, consisting essentially of magnesia (magnesium oxide), occurring in granular forms or in isometric crystals.

Pertaining to the perigee. Perigean tides, those spring tides which occur soon after the moon passes her perigee.

wing of a bird or a gliding aëroplane, within which cyclic or vortical motion of the air occur.

A titanate of lime occurring in octahedral or cubic crystals. [Written also Perovskite.]

A rare mineral, occurring crystallized and in cleavable masses, usually white, or nearly so, in color. It is a silicate of aluminia and lithia.

A kind of shell marble occurring in the Wealden clay at Petworth, in Sussex, England; -- called also Sussex marble.

A hydrous arsenate of lime, usually occurring in silky fibers of a white or grayish color.

A hydrous arsenate of iron occurring in green or yellowish green cubic crystals; cube ore.

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.

strange, unusual, or unaccountable; an extraordinary or very remarkable person, thing, or occurrence; as, a musical phenomenon.

A hypothetic radical (C6H4) occurring in certain derivatives of benzene; as, phenylene diamine.

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

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

oxygen even at ordinary temperatures, giving a faint glow, -- whence its name. It always occurs compined, usually in phosphates, as in the mineral apatite, in bones, etc. It is used in the composition on the tips of friction matches, and for many other purposes. The molecule contains four atoms. Symbol P. Atomic weigh…

Any bird of the order Columbæ, of which numerous species occur in nearly all parts of the world.

uch desires can have no place in a good heart. -- To take place. (a) To come to pass; to occur; as, the ceremony will not take place. (b) To take precedence or priority. Addison. (c) To take effect; to prevail. "If your doctrine takes place." Berkeley. "But none of these excuses would take place." Spenser. -- To take…

A natural alloy of platinum and iridium occurring in grayish metallic rounded or cubical grains with platinum.

A metallic element, intermediate in value between silver and gold, occurring native or alloyed with other metals, also as the platinum arsenide (sperrylite). It is heavy tin-white metal which is ductile and malleable, but very infusible, and characterized by its resistance to strong chemical reagents. It is used for cr…

Manganese dioxide, occurring in tetragonal crystals nearly as hard as quartz.

A colorless transparent mineral, resembling quartz, occurring with castor or castorite on the island of Elba. It is a silicate of alumina and cæsia. Called also pollux.