Marble
Metamorphosed limestone — recrystallised calcite, and the sculptor's stone.
Marble is limestone that has been recrystallised by heat and pressure. The calcite grains grow and interlock, destroying the original sedimentary texture and any fossils it contained, and producing a rock that is uniform in every direction.
That uniformity is exactly what makes it carvable. A sculptor working marble can cut in any direction without the stone splitting along a preferred plane, which is not true of most rocks.
How it forms
Marble is recrystallised limestone. Heat and pressure from burial or nearby intrusion dissolve and regrow the calcite grains, and as they grow they interlock, destroying the fossils, bedding and pore space that the original limestone had.
That recrystallisation is what makes marble useful. The interlocking texture takes a polish that limestone cannot hold, and it lets the stone be carved in any direction rather than splitting along bedding. The impurities present in the parent limestone become the veining and colour: pure limestone gives white marble, clay and iron give the greys, greens and reds.
How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.
How this connects
Where a connection has been confirmed by an outside reference, that reference is named beside it.
is composed of
- Calcite — mineral · 90–100% · recrystallised calcite; the interlocking texture is what lets marble take a polish
- Ruby — mineral variety · an accessory mineral rather than a rock-forming one: ruby grows in metamorphosed limestone where the rock was alumina-rich and unusually poor in silica, which is the classic Burmese occurrence and the reason marble hosts the best of them
is sourced from
- Limestone — rock · by metamorphism rather than by industrial processing
is found at
- Carrara — place
is produced at
- Carrara — place · quarried since Roman times
is named after
- Carrara — place · not the rock type itself, but 'Carrara marble' as a designation
is a source for
- Dimension stone — material · quarried where a stone that takes a polish is wanted
is an input to
- Quarrying — process · the dimension stone trade's premium material, and the reason Carrara has been worked continuously for two thousand years
is an alternative to
- Granite — rock · as building and monumental stone: marble carves far more easily and weathers far worse, which is why it was the sculptor's stone and is not the outdoor one
Sources
- Material WorldOur own writing