Technical Data on our bluestone products is provided for contractors. Please contact us with any additional questions.
Note: The information in this section is relevant to Elk Brook Bluestone only, and is not applicable to other bluestones and/or sandstones. Johnston & Rhodes Bluestone Co. has privately and independently confirmed all testing data below, using exclusively Elk Brook Bluestone samples.
A metamorphic sandstone of the Appalachian Plateau. Formed in the Devonian Age, the Upper Devonian Stone is green and lilac, while the Middle Devonian Stone is dark gray and blue.
Texture: Fine to medium grain.
Color: The basic colors are shades of green, blue, gray, buff, and lilac. Surface colors on natural surfaces are shades of brown, purple, and rust. Sawn material is consistent blues and grays with instances of green and some possible veining.
Chemical Analysis: Silica 77.80%, Alumina 8.40%, Iron Oxide 2.86%, Titanium Oxide .52%, Calcium Oxide 2.27%, Magnesium Oxide 1.20%. Alkalies 2.13%, Sulphur Trioxide .13%, Loss on ignition 2.64%
CERTIFIED TEST RESULTS
(Official copy available on request.)
1.) DENSITY (ASTM C97) lb.siff3) = Average of 169.2
2.) ABSORPTION (ASTM C97) = Average of 0.67 %
3.) COMPRESSIVE STRENGTH (ASTM C170), psi: Dry Parallel, psi = Average of 23,230 psi Wet Parallel, psi = Average of 15,900 psi Dry Perpendicular, psi = Average of 12,770 psi Wet Perpendicular, psi = Average of 11,240 psi
4.) MODULUS of RUPTURE (ASTM C99) psi: Dry Perpendicular, psi = Average of 3,050 psi Wet Perpendicular, psi = Average of 2 410 psi
5.) ABRASION RESISTANCE (ASTM C241) = Average of 79.0
6.) FLEXURAL STRENGTH (ASTM C880) psi = Average of 3,360 psi
NATURAL CLEFT BLUESTONE
5/8″ Nominal Multiple Pattern – 1/2″ to 3/4″ thickness
1″ Nominal Multiple Pattern – 3/4″ to 1 1/4″ thickness
1 1/2″ Nominal Multiple Pattern – 1 1/4″ to 2 1/4″ thickness
2″ Nominal Multiple Pattern – 1 3/4″ to 2 1/2″ thickness
Quarry Cut: Size/squareness is +/– 1/4″. Edges are sawn, pitched, or snapped
Shop Cut: Size/squareness is +/– 1/8″. Edges are sawn.
Exposed Edge Dimensions:
Quarry Cut: Height is +/– 1/4″. Shop Cut: height is +/– 1/8″.
Surface variation not to exceed +/– 1/ 8″ in each square foot of exposed area.
Beds & Joints:
Allow 1 1/2″ mortar bed for setting. Allow 3/4″ mortar bed setting for treads, coping, and sills. Allow 1/2″ for typical joints.
Backs of Stone:
Backs of all pieces may be natural or sawn. Backs of paving may not vary more than 1/2″ in 12″. Backs on treads, coping, and sills may not be more than 1/2 the setting bed.
SAWED-SIX-SIDES THERMAL, RUBBED, OR HONED BLUESTONE
Typical tolerance to be +/- 1/8″. Paving may vary slightly more, depending on setting bed conditions.
Typical size/squareness tolerances for architectural cut stone is +/- 1/8″. Fabrication capabilities may allow the possibility of +/- 1/16″ in certain cases. Paving may vary somewhat more depending on the bed joint conditions and material specifications.
Honed or Rubbed Finish – surface variation not to exceed +/-1 /16″ in each square foot of exposed area.
Thermal Finish – surface variation not to exceed +/- 3/16″ in each square foot of exposed area.
Beds & Joints:
Pieces shall be bedded and jointed as shown on the approved shop drawings, with a minimum of 1/4″ bed or joint dimension. Fabrication capabilities may allow for tighter joints, depending on stone application and field conditions.
Backs of Stone:
Backs or pieces shall be sawn or roughly dressed to approximate true planes.