- ⌂ a blue-gray sandstone that is easily split into thin slabs, used as flagstone
- copper sulfate
- A bluish-gray sandstone used for paving and building.
- A stone similar to this kind of sandstone.
(countable and uncountable, plural bluestones)
- (UK) A form of dolerite which appears blue when wet or freshly broken.
- (UK) Any of several massive stones used to construct Stonehenge.
- (US) A feldspathic sandstone in the U.S.
- (US) A form of limestone native to the Shenandoah Valley
- (Australia) A basalt or olivine basalt.
- (Australia, South Australia) Slate from quarries in or near Adelaide.
- blue notes