INSL will burn if in contact with fire. PUMP and GPMP are indestructible elements (i don't count that BOMB destroys them) This would be just too hard without something like obsidian.
@Darkyhard(View Post) QRTZ should be perfect for your use. Try colouring it if you don't like the colour. It breaks under pressure(depends on its heat for brittle-ness) and melts at quite a high temperature.