Bluestone is not a technical geological
term. It is a commercial trade term, which has been
used to describe a variety of Sandstone, that usually is split and used as
stepping stones,
outdoor paving for walks and patios, etc. (flagstone).
GROUP |
Sedimentary | ||
COMMON ROCK-FORMING MINERAL GROUP |
Siliceous | ||
COMPOSITION |
Quartz, and containing at least 25% and as much as a third of the feldspar mineral group, the matrix may be of quartz , calcitic or ferruginous cementing minerals with other accessory minerals. | ||
HARDNESS |
Hard | MOHS' SCALE | 6 |
POROSITY % |
0.4 - 6.6 | ABSORPTION % | 0.1 - 2.3 |
WEATHERING |
Will fade slightly over time in exterior sittings. | ||
TENDENCIES |
Absorbs oils and other liquids easily. | ||
COLORS |
Medium to dark...bluish-gray and dark greenish. | ||
FINISHES |
Textured...Honed | ||
NOTATIONS |
This stone has been traditionally used for veneers, as a flagstone for paving and as a rough building stone, however this stone is being used more in other sittings, counters, etc. It is important when selecting any stone for a specific application that the natural physical properties and characteristics are understood...It is highly recommended that this stone be treated with a water or oil repellent to help minimize staining and that other modifying treatments be considered if this stone is being considered for counter top material. | ||
Geologically...Bluestone
is a fine-grained arkosic
sandstone, also
geologically referred to
as a feldspathic
sandstone.
The trade term "Bluestone", has been
also applied to some gneiss's and schist's that can
be split and used as flagstone and are similar in color; however, these stones are not a
true
bluestone.