Geoscience Reference
In-Depth Information
of durability. Globally, stone testing requirements are
dominated by two systems, the European standards (EN)
and the American standards (ASTM).
In Europe, to ensure that stone is fit for purpose the
Comité Européen de Normalisation (CEN) requires the
manufacturer to undertake a programme of initial type
testing to evaluate the composition, strength, and
potential durability of every new source. Once it has been
established that the stone is suitable for the proposed
building stone application, further testing of the factory
product is required at regular intervals for quality
assurance. Further testing is sometimes required by the
manufacturer, the purchaser, or third parties to
investigate nonconformities/complaints, confirm identity,
or to diagnose the causes of in-service failure. There are
about 20 European standards covering test methods for
Natural stone resources are variable in character and it is
common to find the good stone of a certain locality
passing within a short distance into less suitable material.
Consequently, the fact that stone from a particular source
has performed well in the past is not reliable proof that
the currently produced stone is of the same quality. The
quality of stone is also influenced by the methods of
extraction, processing, and quality control that are used;
these practices may change over the years. In addition,
stone is now being imported from new sources across the
world, primarily to exploit the cost savings of producing
stone in developing counties with cheap labour.
Therefore, there has never been a greater need for
assurance of stone identity and for dependable prediction
Table 4
Stone classification: relationship between popular commercial and geological petrographic names
(compiled from the terminology in EN 12670: 2002)
Generic grouping
Petrographic name
Commercial group
IGNEOUS
Basalt
BASALT
Dolerite
Picrite
Intrusive:
Granite
GRANITE
Diorite
Gabbro
Peridotite
Syenite
Extrusive:
Rhyolite
Andesite
METAMORPHIC
Gneiss
Quartzite
QUARTZITE
Schist
SCHIST
Phyllite
Slate
SLATE
Serpentinite
MARBLE
Marble
SEDIMENTARY
Dolomite
Travertine
Limestone (polishable)
Limestone (nonpolishable)
LIMESTONE
Sandstone
SANDSTONE
