Slates are silicic-argillaceous rocks
of sedimentary derivation, that develop preferential plans of delamination
(slate fragmentation) used to delaminate the plates. Most slates commercialized
in Brazil are mined in Minas Gerais, being presented in gray, green,
wine, graphite, black and rust colors (multicolor).
The slates are distinguished for internal coverings for the great aesthetic
affinity with wood, metals and tapestry, besides the easy maintenance
and accessible prices. As well as other materials with smooth surfaces,
their natural and polished faces are slippery when wet, however there
is no reason for prejudice against its use, instead of other different
types of stones and ceramic products.
The slate can be distinguished from other natural materials, for the
homogeneous chromatic standards that characterizes them. When in contact
with acid or lemon, slates do not effervesce at all or very discretely,
noticing that graphite and black varieties are chemically more sensible
than the gray ones and these even more sensible than green and wine
varieties.
