Brass White Copper Mountain Ghost Coin Bagua Pendant

Charm coins never circulated. They were cast to be worn, to be handled, and to avert misfortune. The mountain-spirit coin is one type: a spell on one face, bagua on the other, sometimes a ring of thunder pattern at the rim. In the past it was sewn onto a child's clothing or hung from a curtain hook or a door lintel, and what it bought was peace of mind. The characters on charm coins are mostly cast, with sloped edges rather than the sharp cut of a burin. Front and back usually come from two molds, and when the halves don't line up, a step is left at the seam.

Brass and white copper give two different grounds. Brass leans yellow, like gold when new, and moves toward brown with wear while the recesses blacken. White copper leans white, like old silver, and ages to grey without blackening. From the same mold the two metals come out with different temperaments: one festive, one quiet. Brass is softer, so detail rounds off sooner; white copper is harder and keeps its edges longer. Their aged colors differ too, one warm and one cool.

The plaque is round, with relief on the front, bagua in a ring and the spell set vertically in the middle. Both the characters and the trigram lines are cut to varying depth, so raking light shows the layers. The back is flat, with a narrow rim raised at the edge. The plaque isn't thick, sits unobtrusively on the chest, and disappears under a shirt. Spell characters differ from one lineage to another, and the same meaning can come out in several forms once it reaches a plaque. A thick plaque allows deep relief; a thin one can only be shallow-cut.

The fittings come in several options, each for a different habit. The sandalwood cloud cord adjusts for length, has a matte, woody look, and ages along with the copper. The Chopin chain is a single chain that hangs without twisting. The No. 1 floating box is for giving: it suspends the pendant in the middle, so the piece appears to hover when the lid opens. For a gift, cord and box together; the recipient will work out the rest. The cord adjusts long enough for a thick wrist.

The one thing not to do with a charm coin is wash it. The patina on an old copper piece is decades in the making; wash it off and the new copper underneath shows, which looks worse than the dirt did. Dust it with a dry cloth and sweep the crevices with a soft brush. If you must clean, test a small patch at the edge first, and don't put the whole piece in water. Copper dislikes acid: sweat, vinegar and fruit juice all need wiping off, and left alone they pit the surface.