It is acknowledged the finest examples of jet jewellery have been produced in Whitby’s workshops over many years. Jet is formed from waterlogged wood compressed by geological pressure over thousands of years, in much the same way rotted vegetation may be transformed into oil or coal, or under very extreme conditions into diamonds.
Jet has been used since ancient times for ornamental purposes, proved by finds of beads, necklaces and toggles in burial mounds, although never in great quantity. The Romans were certainly known to have worn jet jewellery in the form of hairpins, brooches and pendants (often showing the head of Medusa). It also appears to have been regarded as magical and a kind of cure-all, as Marbodus (c 1430) wrote:
'Lycia her jet in medicine commends;
But chiefest, that which distant Britain sends.
Black light and polished, to itself it draws
If warmed by friction near adjacent straws.
Though quenched by oil, its smouldering embers raise
Sprinkled by water, a still fiercer blaze;
It cures the dropsy, shakey teeth are fixed,
Washed with the powder’d stone in water mixed.
The female womb its piercing fumes relieve,
Nor epilepsy can this test deceive;
From its deep hole it lures the viper fell,
And chases far away the powers of hell.
It heals the swelling plagues that gnaw the heart,
And baffles spells and magic’s noxious art.
This by the wise and surest test is styled
Of virgin purity by lust defiled.
Three days in water steeped, the draught bestows
Ease to the pregnant womb in travail's throes.'
That the rhyme was believed is supported by finds of jet crosses attached to the witch posts of houses in the area. Of Rowan wood, these posts were thought to protect against witchcraft.
Jet was certainly being worked during the existence of Whitby abbey as beads were found in the abbey’s midden during excavations in 1867, and the account rolls for 1394 mention gagate (jet) rings sold to Robert Car. The mineral was worked by knife and rubbing stone, and it was not until about 1800 that a Captain Tremlett persuaded a Matthew Hill to produce jet beads by turning on a lathe. The experiment was successful and trade increased steadily until by 1850 there were several employers.