Flexible Sandstone
This, I contend, is the world's strangest rock. It
is a naturally occurring sandstone that is freely flexible. It's called
itacolumite. This piece was given to my mother-in-law by her late uncle
many years ago when he returned from a trip to India.
When I first saw it I thought it was synthetic,
and maybe contained some internal structure. So my initial thanks
on my path to identification go to my dentist, Robert Anderson of the Brock
Street Clinic, Bath, who X-rayed it so that we could see that it had a
uniform density and nothing inside but more rock.
My thanks then go to the geology section of the Natural
History Museum in London who kindly identified the sample properly.
They have a much larger sample about 1m long from Jujjur 150 kilometres
north-west of Delhi. There are also deposits in Georgia
and Stokes and McDowell Counties, NC, in the USA. In Stokes
County, local names for it are `bending rock' and, more poetically,
`limber grit'.
The stone is formed from grains of quartz that are
bonded together. A solvent then selectively dissolves the bonds leaving
an interlocked but lose structure that will extend freely in any direction
for a short distance then stop. The result is a flexible rock.