Pendant made with full color sandstone

Hello,

I need to create small pendants (square bounding box of 4cm sides) of different shapes (square, circle, triangular) with just a small hole for a thin necklace. On one side I'll have a colored picture and on the other a bw QR code, so I'll need to make it in full color sandstone.

I have some doubts:
1) I've read that sandstone is more suitable for decorative objects because more fragile, but my 3D object is extremely basic, do you think it usable as pendant without breaking (I'd like an opinion...but I'll test it anyway )
2) I've read that it stains with water and this may be a major problem. Is there anything I can do to make it more protected? anything I can spray on it, transparent paint...
3) I was thinking of making it 3mm thick, would you suggest to make it thicker? I can go up to 5mm but I would prefer to make it thinner.

I also thought of creating just the 3D shapes in a stronger material, white, and then have another service to make a sublimation print on both sides, but It would be more expensive, and I would prefer, if possible, to directly have delivered the final product.

Thanks!

I have only limited experience with sandstone, but can give you a bit of advice.

1) The material is reasonably solid and I think it can be used as a pendant. In fact, there are some Shapeway shops that sell necklace pearls and other jewelry items in sandstone. Make sure that the hole for the necklace is not too close to an edge. Rounded or beveled outside edges also help.

2) Indeed, the colour dissolves with water. Covering it with varnish (not water-based!) will protect it. For jewelry, make sure the varnish is skin-compatible.

3) Not sure about what would be a safe thickness. But there is a 3 mm thick poker chip made of sandstone

Greetings
Dragoman

Thanks! I'll try some samples at different sizes.