Usually mirror is glass, silver plated, and then paint is applied to prevent the silver from tarnishing. Even if you have mercury on the back of the mirror, it shouldn’t present a danger. No one will be handling it, flaking it off and eating or licking it. By your question, it seems you are worried it is dangerous. I have antique pewter, but we don’t use it for food because it probably contains lead. I don’t use mugs or dishes made in China because I don’t trust them to use lead-free glazes. I also love redware, but would only display antique pieces and never eat from them, again because of the danger of lead in the glaze.

'Don't lick the mirror' is good advice.

Thank you. Yes, I am concerned, as I've read the mercury off gasses small amounts and I have three young children. Honestly, I had never heard of mercury in mirrors before, until reading about it on a thread about antiques.

Your mirror should be silver unless it was made decades before the house was built. Mercury stopped before the 1900's. Silver was used in the 20's.

Even if it were mercury, after a centry off gassing wouldn't be an issue anymore. But still, mirror licking should be discouraged regardless of what the backing material is.

Good thing there's no mirror licking happening. Thank you!

Can not find any on-line info supporting a concern re mercury being a hazard due to use in mirror backings.

Do you have any amalgam tooth fillings? I do.

The vapor pressure of metallic mercury at room temperature is pretty much zero, I don't think "off-gassing" is much of a concern. Also metallic mercury is pretty unreactive, the real toxicity comes with organic mercury compounds that can penetrate and interact with biological targets.

Real mercury backed mirrors are very rare these days and quite beautiful. A much richer look than the silver used now.