Sterling silver and 2 AAA Rubies. I love the concave faced tamps, because I used to use a golf tee and found that they formed the perfect top to the cherry, IMO. The depth of the concave is only about half of the shown dimensions, because I hand forged it to have tapered edges. And, rubies represent fire and passion, which goes long with how I feel about this hobby. I can stare into a ruby for hours, with it's depth of color and memorizing play on light. I know most guys don't care much for gemstones, but one of my other passions as a jeweler has always been rockhounding and lapidary.