Antilithium

Heavy antinuclei, if observed, would also indicate that nucleosynthetic processes are taking place in these antimatter regions, since the usual matter-symmetric cosmologies have no other provision for manufacturing antimatter heavier than antilithium.

The pinhead contained only a twentieth of a gramme of antilithium, but that's more than sufficient for our purposes.

Even unshielded, it would take antilithium or highmatter to cut through the adamantine plate on the dorsal hull.