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corundum

(Encyclopedia)corundum kərŭnˈdəm [key], mineral, aluminum oxide, Al2O3. The clear varieties are used as gems and the opaque as abrasive materials. Corundum occurs in crystals of the hexagonal system and in mass...

Fox, river, United States

(Encyclopedia)Fox, river, 176 mi (283 km) long, rising in S central Wis. and flowing SW to within 1.5 mi (2.4 km) of Portage, Wis., on the Wisconsin River, then NE through Lake Winnebago into Green Bay, an arm of L...

jade

(Encyclopedia)jade, common name for either of two minerals used as gems. The rarer variety of jade is jadeite, a sodium aluminum silicate, NaAl(SiO3)2, usually white or green in color; the green variety is the more...

bowls

(Encyclopedia)bowls, ancient sport (the bocce of Caesar's Rome is still played by Italians), especially popular in Great Britain and Australia, known as lawn bowls or bowling on the green in the United States. It w...

Colorado–Big Thompson project

(Encyclopedia)Colorado–Big Thompson project, constructed by the U.S. Bureau of Reclamation to divert water from the headstreams of the Colorado River to irrigate c.720,000 acres (291,400 hectares) of land in NE C...

chrysoberyl

(Encyclopedia)chrysoberyl krĭsˈəbĕrˌĭl [key] [Gr.,=golden beryl], a beryllium aluminate used as a gem. It has a vitreous luster and is transparent to translucent. The more valuable cat's-eye is a variety of c...

olivine

(Encyclopedia)olivine ŏlĭvˈēn [key], an iron-magnesium silicate mineral, (Mg,Fe)2SiO4, crystallizing in the orthorhombic system. It is a common constituent of magnesium-rich, silica-poor igneous rocks; metamorp...

garnet

(Encyclopedia)garnet, name applied to a group of isomorphic minerals crystallizing in the cubic system. They are used chiefly as gems and as abrasives (as in garnet paper). The garnets are double silicates; one of ...

Equisetophyta

(Encyclopedia)Equisetophyta ĕkˌwəsətŏfˈətə [key], small division of the plant kingdom consisting of the plants commonly called horsetails and scouring rushes. Equisetum, the only living genus in this divisi...

bird of paradise

(Encyclopedia)bird of paradise, common name for any of 43 species of medium- to crow-sized passerine birds of New Guinea and the adjacent islands, known for the bright plumage, elongated tail feathers called wires,...