Can a UV Laser Engrave Slate?

Yes. Makers have logged slate engravings on the xTool F2 Ultra UV, from a light grey frost to a brighter white mark. Slate is a dark stone, so the UV mark reads as contrast without paint.

That answer is not a recipe. Slate from one supplier can take more energy than slate from the next, and a damp blank can chip. The chart and the test method live in xTool F2 Ultra UV slate settings.

What the mark actually is

A 355 nm source breaks material with less heat than a diode or CO2 beam. On slate, Atomm's calibration project describes that as high-precision ablation with little thermal spread (Atomm grid). You see a light mark in the dark face of the stone. You do not need a paint fill for the engraving to show.

What still goes wrong

• Grey instead of white usually means too little energy: faster speed, or only one pass, when the log you copied used two.
• Chipped edges usually mean too much energy, or a stone that was not dry.
• A new box of coasters looks different because the mineral mix changed. Run the grid again.

Where to start

The most useful single log we found is 100% power, 150 mm/s, 2 passes on 4.5 mm rectangular rock slate, from Atomm's settings roundup (source). One other recipe publishes 40 kHz. Treat both as the first square of a test grid, not as the finished preset.

FAQ

Does slate need paint or a coating?

No. The contrast comes from a light mark on the dark stone. A light coat of mineral oil can deepen the stone around the mark. Test that on scrap first.

Can I engrave a photo, or only text?

Both. Photos need a clean background, and they often need to be inverted because the laser marks light on dark. Test a small crop before the full coaster.

Is a UV laser required, or will any laser mark slate?

Other lasers can mark stone, often with more chipping. The logs on this site are for a 355 nm galvo, the F2 Ultra UV. Do not copy a diode preset across.