Chemical Composition
SiO2 Silica 45.6 - 56.5%
Al2O3 Alumina 16.0 - 25.0%
Fe2O3 Iron 5.4 - 8.4%
TiO2 Titania 0.7 - 1.9%
MnO Manganese 0.0 - 0.1%
MgO Magnesia 2.6 - 3.8%
CaO Calcium 1.6 - 4.2%
Na2O Sodium 0.5 - 1.5%
K2O Potassium 2.8 - 6.5%
S Sulfur 1.1 - 2.7%
C Carbon 1.5 - 2.1%
CO3 Carbon dioxide 0.8 - 5.5%
H2O Water 0.1 - 0.3%

Chemical Resistance
(No reaction or penetration after 8-hour immersion in)
70% HNO3 Nitric Acid
36% HCl Hydrochloric acid
60% HClO4 Perchloric acid
H3PO4(Conc.) Phosphoric acid
HC2H3O2 Acetic acid (glacial)
H2CrO4 Chromic acid
30% NaOH Sodium hydroxide
Na3PO4 Tri-sodium phosphate
(Some reaction and penetration after 8-hour immersion in)
96% H2SO4 Sulfuric acid
48% HF Hydrofluoric acid

Coefficient of Friction
Dry
Wet
Finish: Static Dynamic Static Dynamic
Sand .69 .66 .65 .61
Cleft .81 .79 .87 .83

Weight
Specific Gravity 2.79 - 2.83
Mass 170 - 180 /cu. ft.
Weight @ 1" Thk. 15 lbs. / sq. ft.

Electrical Resistance
Dielectric Strength -
7,000 volts minimum for 1" Thickness.
Ohmic Resistance -
700,000 ohms/in.3 Minimum Fresh quarried slate.
2,500,000 ohms/in.3 - Minimum for dried slate.


Life Expectancy
At the present time, there is no known accelerated test method for simulating the life expectancy of any natural building stone with any reasonable degree of correlation and reproducibility.
Mineral Composition
Quartz 30.0 - 53.2%
Sericite/Illite 24.7 - 37.0%
Feldspar 0.0 - 8.3%
Pyrite 4.0 - 6.4%
Dolomite 3.7 - 5.3%
Calcite 2.0 - 10.0%
Chlorite 3.4 - 5.0%
Rutile 0.0 - 0.5%
Carbonaceous
& Water
2.5 - 3.6%

(Click on Desired Topic)
  • Physical Properties
  • Interior Flooring
  • Applied Finishes
  • Installation Details
  • Exterior Paving
  • Basic Specification
  • Panels
  • Anchors, Dowels, Etc.
  • Window Stools
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  • The Structural Slate Company
    222 East Main Street
    P.O Box 187
    Pen Argyl, Pennsylvania 18072-01
    1.800.67.SLATE or Fax: 610-863-7016

    ssco1@ptd.net

    A.S.T.M. Specifications
    C-629 & C-406:
    C-121 Absorption (Max. %)
    Exterior .025%
    Interior .045%
    C-217 Acid Resistance (Weathering)
    Exterior.015"
    Interior.025"
    C-120 Modulus or Rupture (Min, psi)
    (Across Grain)
    Exterior
    9000 psi
    Interior 7200 psi
    (Along Grain)
    Exterior
    7200 psi
    Interior 5500 psi
    C-1353 /
    C-241
    Abrasion
    Resistance.
    8.0 min. Ha.
    ** Note **
    C-1353 is a new test method of which historic values have not been established as yet. New test values may be lower than 8.0 min. Ha.