600-Year-Old Amethyst Jewel Found in Polish Castle Moat Sparks Intrigue

Perhaps the noble traveler tossed it into the moat in a fit of rage. Or maybe it slipped unnoticed from her silk-clad shoulder as she crossed the timber bridge. Whatever the reason, a 600-year-old aristocratic jewel has recently emerged from the muddy moat of Castle Kolno in Poland, offering modern archaeologists a glittering glimpse into medieval luxury, status and symbolism.

The remarkable find — a vibrant amethyst set in fire-gilded silver — was likely part of an ornate brooch or, less likely, a coronet. Its design features a cabochon amethyst cradled in a cone-shaped claw setting, surrounded by a delicate halo of openwork rays or palmette petals. Traces of lead solder and a silver pin on the back suggest it once adorned a larger piece of ceremonial jewelry.

While medieval jewels are usually unearthed in tombs or hidden hoards, this discovery stands out for its everyday context. Archaeologists from the University of Wrocław, led by Lech Marek and Beata Miazga, found the piece during excavations of Castle Kolno’s moat sediments, nestled between the remains of 14th-century timber bridge posts.

Built in the early 13th century, Castle Kolno once guarded a customs house on the border between the duchies of Opole and Brzeg. By the 15th century, it had become home to wealthy knights before being destroyed during Silesian civil wars in 1443.

To confirm the artifact’s composition, Marek’s team employed advanced technology, including Raman spectroscopy — a laser-based method that identifies minerals by analyzing their molecular vibrations. This confirmed the gemstone as amethyst.

The metal was analyzed using X-ray fluorescence and scanning electron microscopy, revealing it to be high-quality silver finished with fire gilding —a medieval technique that bonded gold to the surface using mercury, leaving a lustrous gold appearance while saving on costly materials.

The results of Marek and Miazga's study were published online July 11 in the journal Antiquity.

Amethysts held special meaning in the Middle Ages, beyond their aesthetic appeal. According to medieval folklore, they protected wearers from intoxication, venom, treason and even bad dreams. Their rich purple hue symbolized faith, modesty and martyrdom, while in religious and courtly circles, the stone’s mystical qualities were believed to bolster moral virtue and spiritual strength.

The jewel from Castle Kolno was undoubtedly a marker of elite status — what historians call an example of “conspicuous consumption.” Its presence in the moat raises tantalizing questions about how it came to be lost. Was it a simple accident, or a flash of ill temper? For now, the mystery remains as captivating as the jewel itself.

Credits: Images by Lech Marek; CC BY 4.0.