A moss-covered Buddhist temple door step, similar to a Sri Lankan "Moonstone" (Sandakada pahana), brought £553,250 ($844,540) to Bonhams London yesterday (April 23).
The sale price represents a 1,744% increase on the item's £30,000 top estimate.
Fondly known as "The Pebble" by its previous owner, Bronwyn Hickmott, the carved granite "Moonstone" is over 1,300 years old and weighs a hefty three quarters of a ton.
Called a "museum piece" by Bonhams' Alice Bailey - a specialist in Indian and Islamic art - it is believed to be one of only seven extant examples.
Following the auction, Hickmott told the Sun newspaper: "Everyone just pooh-poohed our belief that it was special.
"When it reached more than £40,000 my jaw dropped to the floor. We are just overwhelmed."
The beautiful temple step, which Hickmott kept in her Devon garden, features a curved procession of animals, including lions, birds, elephants and horses, as well as a lotus blossom and a dense bed of curling leaves.
Bonhams' Sam Tuke reports Hickmott as commenting that "she had known and loved it all her life. She loved running her fingers around the animals carved into the stone."
The temple stone was originally removed from "Brakenhill", a mock Tudor property in East Sussex, UK, once owned by Hickmott's father. One time home of William Murdoch Tyne - a Scottish civil engineer who worked in Ceylon between 1915 and 1937 - it is thought that Tyne brought the stone back to Sussex.
The vendor's family then moved into the property and the stone passed into their possession.
Following her father's death, unable to part with the stone, Hickmott transported the item from Brakenhill to her present home in Devon. It has lain in her garden ever since.
Equivalent stones can be found in Sri Lanka's ancient city of Anuradhapura, at some of the country's most culturally significant temples and monuments.
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