Flooring Tile - What adhesive do I use to adhere travertine to metal on zero clearance fireplace?

I am remodeling a fireplace and am looking to place tile over a portion of the metal face on a zero clearance fireplace. The original contractor utilized some form of an adhesive from a tube that held quite well, though I have been unable to find anything that will work.

The original contractor placed smaller tiles directly to the metal with some tiles overlapping drywall. In my case, I will be using 16” travertine that will mostly (10” to 12”) be attached to the drywall, however 4” to 6” will overlap the metal.

I contacted the manufacturer of the fireplace and they state that it is fine to tile over the areas I am referencing, however could not recommend a product for setting the tile. They did state that it should withstand 250 to 300 degrees however.

Since I am using travertine, I also need something that will not bleed through.

So far, recommendations that I have received have consisted of sealant, though to me sealant is a “sealant” and will not act as an adhesive.

Any input would be incredibly helpful as I have has no success as of yet.

Thank you!

Check with the mfg. of thin sets for one that will bond to metal.Thin set being a cement is fine with the heat (think fire place bricks)