Sardonyx

Soldiers carried it, which is the part you will repeat.

Roman cutters used it for cameos because its layers lie flat and parallel, so a carver can cut down through the red and leave a white figure standing on a dark ground. It was August's birthstone before peridot took the slot. Soldiers carried it, which is the part you will repeat.

The layers lie flat because they settled by gravity.

The layers lie flat because they settled by gravity in a cavity, which is exactly what a cameo cutter needs to undercut a pale figure on a dark ground. Roman signet stones ran on it, and Roman tradition gave it to soldiers for steadiness. It was August's birthstone before peridot.

One stone, two registers, white face on dark ground.

Roman carvers cut cameos from it because the layers lie flat, so you can undercut the pale one and leave a white face standing on a dark ground. The bands settled out by gravity in a cavity, which is why they are level rather than curved. One stone, two registers.

Everything in it settled out and stayed level.

The layers lie flat and parallel because they settled out under gravity in a cavity rather than following the walls, which is how it separates from any other agate. Roman soldiers carried it. Everything in it settled and then stayed level.

Undercut the white and a pale head stands on dark.

August's birthstone before peridot took the slot in 1912. The bands lie flat and parallel because the layers settled by gravity, which is precisely what a Roman cameo cutter wants: undercut the white and a pale head stands out against a dark ground. A face, built in layers.

The bands lie flat because they settled by gravity.

Roman cutters chose it because the bands lie flat and parallel, settled by gravity in a cavity instead of following the cavity wall. They undercut the white layer so a pale figure stands on a dark ground. It held the August birthstone slot until peridot took it.

One colour held against another, and neither one moving.

The bands lie flat and parallel because the layers settled by gravity in a cavity instead of following its walls. Roman carvers undercut the white so a pale figure stands against a dark ground. The whole art is one colour held against another and neither one moving.

Rome filed it under Mars and gave it to soldiers.

Flat parallel layers of red-brown sard and opaque white, settled by gravity in a cavity instead of following its walls. Roman carvers cut the pale layer away to leave a figure standing out of a dark ground, which is where the cameo comes from. Rome filed it under Mars and gave it to soldiers.

Roman carvers undercut the layers to leave a pale figure standing.

The layers lie flat and parallel because they settled by gravity in a cavity, which is what separates it from ordinary agate. Roman carvers undercut the layers to leave a pale figure standing on a dark ground. It was August's birthstone before peridot took the slot.

Roman cutters used the geometry, not the colour.

The bands lie flat and parallel instead of curving, because these layers settled by gravity in a cavity rather than following its walls. Roman cutters used that geometry for signet stones, undercutting a pale figure onto a dark ground. It held August until peridot took the job.

The bands lie flat because they settled under gravity.

The bands lie flat because they settled under gravity in a still cavity, rather than curving around a wall the way ordinary agate does. That flatness is what makes cameo carving possible: cut through the pale layer and a figure stands out against the dark. Rome ran on it.

The layers lie flat because nothing was moving.

The layers lie flat because they settled under gravity in a still cavity, rather than curving around a wall like ordinary agate. Carvers cut down through the pale layer so a figure lifts out of the dark ground beneath. Rome put it on soldiers and on wedding rings.

Sardonyx is carried for courage, protection and boundaries. Straight-layered agate in red-brown and white, and the standard material for Roman cameos and signet stones because the layers can be undercut to leave a pale figure on a dark ground.. Tradition links it to the root, sacral chakra.

Frequently dyed or heat-enhanced to sharpen the contrast between layers, using the same sugar-acid and iron-staining processes as onyx and carnelian.. Look for straight parallel layers, not concentric rings, that is sardonyx rather than a standard agate. Scratches glass.. Frequently dyed or heat-enhanced to sharpen the contrast between layers, using the same sugar-acid and iron-staining processes as onyx and carnelian.

A short rinse is fine for sardonyx, then dry it.