The outstanding physical and mechanical properties of serpentine schist make it suitable for a wide range of applications. It possesses outstanding flexural strength, which makes it quite unique. It also boasts high compressive strength and considerable resistance to weathering so that it is immensely durable. Serpentine schist is less slippery than many building stones, due to its rough (but not disjointed) surface texture, which explains its popularity for paving and wall cladding applications. Valmalenco serpentine schist is classified as a STONE in Italian UNI standard 8548. The commercial name, Serpentinoscisto, is listed in Annex A to the EN 12440 standard entitled “Natural stone. Denomination criteria”. Technical tests for the certification of Serpentinoscisto are performed according to the Technical Standards detailed in Attachment A (Chapter I B) of Regional Law No. 10 dated 06.03.1990 for the Valdaosta autonomous region. It is apparent from the technical data outlined below that Serpentinoscisto is the roofing stone that best fits the requirements of the aforementioned regional law.
Petrographic and technical properties
Mineral composition and petrographic definition
Main minerals: antigorite and olivine (comprise 80-90% of the stone’s composition) and, in decreasing amounts, clorite, magnetite, pyroxene. The antigorite and olivine are deposited in parallel foliations, which results in extremely even schistosity.
Bulk density (kg/m3): 2795 kg/m3
Water absorption (% of weight): 0.08 %
Compressive strength (MPa): (direction of loading perpendicular to foliations) 301 MPa
Compressive strength (MPa): (direction of loading parallel to foliations) 136 MPa
Flexural strength (MPa): 96.7 MPa
Average flexural freeze-thaw strength (MPa): 93.4 MPa
Weather resistance (affected layer in mm): 0.01 mm