Intaglio is the opposite of a cameo as its carved into wood, ivory or stone, while a cameo is a raised carving. Commonly intaglios were thought to bring good luck and were "trinkets" from Europe. Their roots date back to ancient Rome in which they were like a seal to mark your belongings, or an insignia in your ring. You can find them in rings, jewelry, and framed, with some examples below. I love how they are so delicate and look amazing framed, whether it's a singular one, a grouping, or a colored background.
Intaglios framed en masse. Love the blue background. BrownRigg
So many arranged closed together. Ann Connelly Fine Art
Intaglios stand out with the dark brown background. Amy D. Morris
Marine Life Collection by Karen Robertson
Love how they are arranged mixed with tiny intaglios. Swedish Dekor
Notice the intaglios on the left wall above the desk. Suzanne Kasler
Lone framed intaglio. Metro News
This amazing vintage collection was at Christie's.