[2][3] Five stones support the roof, a massive slab measuring 18 by 9.5 feet (5.5 m × 2.9 m) and weighing an estimated 12.5 tonnes (12,500 kg), which has slipped from its original position, with one end resting on the ground.

A local legend is associated with the chamber in that it is said that the quoit possesses mystical powers and that removed stones from the structure would soon mysteriously find their way back in the middle of the night.

[2] In 1754 and in 1769, before the roof had fallen, the quoit was analysed by the antiquary Dr. William Borlase (1695–1772), who described and provided detailed drawings of it and published some of his findings in his Antiquities of Cornwall (1769).

[3] In 1861, a local farmer proposed to convert the monument into a cattle–shed by removing one of the upright pillars and drilling a hole in the sloping capstone.

Traces of drill–holes can still be seen in the stone[5] In 1882, a member of the Borlase family came to the defence of the quoit again when the Penzance Natural History and Antiquarian Society visited the site.

Underneath it they found what Mr. Borlase said was an ancient whetstone, which no doubt was buried with the dead, in order that he might have something to sharpen his weapons with in 'the happy hunting grounds' to which he was supposed to have gone.