@Mark King It looks like a home made (clay/pewter?) good luck charm/talisman. The triangle with the two segments looks similar to those found on different charms known in Jewish Mysticism or The Key of Solomon; usually representing a constellation or sign, though I can't figure out which one yours is depicting. Did you happen upon it or did you get it from a friend or relative? Did they happen to be avid metal detectorists, rock hounds, or treasure hunters? It was popularly used during the 18th/19th century by treasure hunters. For reference, take a look at Jupiter's Talisman.