01 / Geological family

Origin and composition

Geological family
Metamorphic
Origin and composition
fine siltstone with pervasive cleavage, commercially called slate
Origin
Valentia Island, Kerry, Ireland
Appearance and identification
a relatively uniform purple colour

Metamorphic rocks result from existing rocks changing under new pressure, temperature and fluid conditions. Marbles and quartzites can show recrystallised textures; gneisses, slates and phyllites often show oriented minerals and recognisable planes. These structures matter for cutting direction, thickness and interpretation of mechanical tests. Metamorphic origin alone does not establish suitability: composition, weathering and processing remain decisive.

02 / History and curiosities

History and curiosities

It has been used for roofs, industrial floors and billiard tables.

03 / Applications and design

Applications and design

Slabs, floors, roofing and fabricated objects.

Finishes and processes ↗

04 / Technical interpretation

What to ask your supplier

Honed and split finishes have different uses; check the actual product and finish.

05 / Care and maintenance

Care and maintenance

Remove dust and grit with soft tools, wash with a compatible neutral cleaner, then rinse and dry. Identify composition before using stain or scale removers: carbonate stones are acid-sensitive. Test every treatment in an inconspicuous area. An impregnator can reduce absorption but does not make a material waterproof or stain-proof.

Thoughtful cleaning, protection and maintenance ↗

07 / Sources and further reading

Sources and further reading

Editorial method ↗