Agate

Agate (Gr. Agathos – “good”) – a semi-precious mineral, multicolored, striated chalcedony variety. Its name might also derive from the river Achates (today’s Dirillo) on southern Sicily, where it was found since antiquity.

Agates are created in geodes. They consist of many multicolored, usually pale layers.

As with other stones people living in the Middle Ages (at least according to the written sources) did not discern blue stones, oftentimes just calling them all “sapphires”. It’s a very common name in contemporary sources; mentions in the written sources do not necessarily have to represent actual sapphires.

Undoubtedly many extant examples of jewellery are decorated with real sapphires, but there are some very special pieces like the brooch from the treasure from Sroda Slaska. Its centerpiece is a 2cm diameter cameo with an eagle, made from blue chalcedony.

Because of the sapphires, arguably their “king”, blue stones became a symbol of faith and heavens themselves, of trust and light. The sapphire belonged to St. Andrew.

Blue stones were also thought to cure bubonic plague, liver illnesses, fevers, bad spleen and eyes.