Engraving on "Crystal K9"?

I have seen recently on Aliexpress a new kind of key rings, made of so-called ‘crystal K9’:

They come with a led and a small battery, and they shine various colours. The logo seems to be laser engraved. I wonder if anyone knows what this ‘crystal K9’ is and if I can engrave it using my CO2 laser ?

Furthermore, it seems that they engrave the picture inside the crystal. Is it possible to do that, for example just by focusing the light in the middle of the crystal thickness? Or is it just 2 half crystals (one engraved) glued to each other? I doubt it though, because there would be some glue traces visible when it is lit…

Has anyone ever tried this ?

K9 Crystal seems to a type of borosilicate crown glass with a lead content of about 9%

While I’m pretty sure you COULD probably engrave it with a CO2 laser, I do NOT think you WOULD want to because of the lead content.

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I mean I see lots of people offering laser engraved K9 glass, but if they are are actually using a leaded glass they are generating lots of micro-fine lead glass particles. Would be a high safety issue to me.

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Ah, it’s sub-surface. Thanks for the video. :smiley:


Very interesting, thanks for all your answers.


I’m trying on 9mm thick plexiglas, but there is no way to focus the beam inside without engraving also the upper surface.

I don’t think so. Acrylic is probably to opaque to the CO2 laser.


But do you think it would work that way with the K9?

If it were they would probably make CO2 laser lenses out of it… Leaded glass has a high refractive index and is used for lenses as a result.

No, it doesn’t look like lead crystal is transparent to far infrared.

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I’ve engraved “ordinary” borosilicate glass without any complications, although I’m not equipped to determine if lead particles were released. When I engrave glass, I apply a dish soap/water mixture to keep fracture debris in hand and to cool the glass. Without the soapy water, the glass gets blistering hot.