- bluish-grey sandstone useful for paving and building
- Blue vitriol.
- A grayish blue building rock, as that popular in the eastern United States.
(n.) Blue vitriol.
- (letter.) A grayish blue building stone, as that widely used when you look at the eastern United States.
Gibson and begun in 1883; St Peter's Episcopal Church (French Gothic), of Hudson River bluestone; Emmanuel Baptist Church, of white granite; the Madison Avenue Reformed Church; and St Joseph's (Roman Catholic), of bluestone and Caen stone with marble trimmings.