An olive-green sandstone containing glauconite

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Greensand \Green"sand`\ (-s[a^]nd`), n. (Geol.) A variety of sandstone, usually imperfectly consolidated, consisting largely of glauconite, a silicate of iron and potash of a green color, mixed with sand and a trace of phosphate of lime. Note: [hand]Greensand ...

Wikipedia Word definitions in Wikipedia
Greensand is a type of sand or the sandstone created from said sand. Greensand or green sand may also refer to: Green sand, used in sand casting. See Sand casting#Green sand Greensand, New Jersey , an unincorporated community in the United States Greensand ...

WordNet Word definitions in WordNet
n. an olive-green sandstone containing glauconite

Wiktionary Word definitions in Wiktionary
n. (context geology English) A greenish sandstone containing glauconite.