organic
Jet
- Also known as
- black ambergagate
- Crystal system
- amorphous
- Hardness
- 2.5–4 on the Mohs scale
- Lustre
- waxy
- Colour
- Deep black
- Where it forms
- From driftwood — chiefly of the monkey puzzle family — waterlogged, buried in marine mud and compressed. Whitby jet formed in the Early Jurassic, around 180 million years ago.
- Chiefly from
- Whitby, Yorkshire, EnglandAsturias, SpainColorado, United States
Why it is that colour
Carbon. Jet is a variety of lignite coal, formed from a specific wood under specific conditions, and it is black for the reason coal is.
Safety
Safe to handle. Very light, warm to the touch, and soft enough to scratch easily.
Where it comes from
Whitby jet is collected from a small stretch of Yorkshire coast, largely from the beach rather than mined, and genuine material is scarce. Most black jewellery sold as jet is glass, vulcanite or plastic.
Historical use
The defining material of Victorian mourning jewellery. When Prince Albert died in 1861 the court went into prolonged mourning, jet was the only ornament permitted, and Whitby supported an industry of some fourteen hundred workers. The fashion collapsed within a generation and the industry with it.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
What is attributed to it, and since when
Used for amulets from the Bronze Age and named from the Greek town of Gagas. Like amber, it takes a static charge when rubbed, and both classical and later sources connect it with protection against the evil eye. Its European association with mourning is genuine but is chiefly Victorian.
Described, not endorsed. Dating a claim is not the same as assessing it — but an association that first appears in a book published in 1985 is not an ancient inheritance, whatever the label says. A sincere account of feeling better is compatible with the stone doing nothing — see the placebo effect.
Sold as this, but not
Worth knowing
Jet is fossil wood, and like amber it fails the definition of a mineral on the grounds of having been alive. The two are often paired, and for good reason: both are light, warm, organic, take a high polish, and become electrostatic when rubbed. The Greeks noticed the second property in both.
The Victorian mourning industry is a compact lesson in how a material's value can be entirely social. Jet was worth a great deal for roughly forty years because one widow set a fashion, and worth very little afterwards. The stone did not change.
Identity checked against IMA-CNMNC master list, June 2025.