Entities aligned with Mercury: What metal should I engrave their sigil?

Greetings! As of lately Marbas has been awesome and I intend to reward him by getting his seal engraved upon a metallic plaque. Thing is, I cannot find what is the most appropriate metal do get that done (because sure as Hell people are bound to run away if I ask them to somehow etch things on mercury, right?).

Have you ever found yourself in this kind of situation? What did you do?

Liquid mercury(quicksilver) theoretically or I’m pretty sure brass is the other option or mixtures of metal or metallic alloys.

Jospeph Peterson’s Complete Magician’s Tables - Table M17 - Rank - President, Metal - Mercury, Incense - Storax

Metals associated w/Mercury according to Veritable Key of Solomon - Quicksilver, Antimony, Stones - Emerald, Topaz, Porphyry

Time it took to look up, ~4 minutes. Keep the tools you know you’ll need at hand.

Brass is for Earls under Mars, but it must be Copper mixed with silver, not just any brass

Thank you, the both of you.