Jet's most concentrated modern association traces to one town and one bereavement. Whitby, on the Yorkshire coast of England, sat above a rich seam of high-quality jet and had built a local carving industry around it well before the material's national moment arrived: when Queen Victoria adopted jet mourning jewelry after Prince Albert's death in 1861 and wore it for the rest of her long reign, Whitby jet became the socially expected material for respectable mourning wear across Britain, and the town's workshops expanded rapidly to meet the demand.
That association was strong enough that jet is still popularly called "black amber" or associated primarily with grief in much of the English-speaking world, even though the material's own history, worked since the Bronze Age and appearing in prehistoric and Roman British grave goods, long predates the specifically Victorian meaning layered onto it.
The demand had a formal structure behind it. Victorian mourning etiquette graded bereavement into stages, deep or full mourning followed by second and half mourning, each with its own conventions about dress and ornament, and jet was one of the few materials a woman in the first stage could wear at all, where anything bright or reflective was ruled out. That made it less an option than a requirement for anyone observing the code.
The same specificity is why the Whitby trade fell about as quickly as it rose. Once the fashion relaxed towards the end of the century, and once cheaper substitutes arrived, chiefly black glass sold as French jet and moulded vulcanite, the town's workshops had little else they were set up to make.