How does one distinguish French jet from genuine jet?

Weight and temperature: being glass, French jet is markedly heavier and always cool in the hand, whereas jet is strikingly light and warms to body temperature within seconds. Visually, edges and breaks help - glass shows a conchoidal fracture, jet a dull one. Under UV light jet fluoresces faintly yellowish, while glass stays dull.

Why was French jet so successful?

Whitby jet was caught in a high-Victorian supply bottleneck: extraction was limited, prices rose, and the middle classes could not afford original pieces. French jet was three to five times cheaper, virtually indistinguishable to the eye and available across Europe through Parisian and London wholesalers. It was the first mourning jewellery of the middle class.

Does French jet have any collector's value?

Yes, although markedly below that of jet. Well-preserved brooches and necklaces from the peak period (1870–1890) are sought after, especially with an identifiable manufactory mark (Parisian workshops occasionally signed their work). Damaged material is practically worthless - glass cannot be restored.

French Jet

French jet is a misnomer - not jet at all, but deep black pressed glass which, from the 1860s onwards, conquered the Victorian widow's-mourning-jewellery segment as inexpensive mass-produced ware.

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