Gallium || Ga
This element is so interesting. It has a melting temperature of about 85 degrees Fahrenheit, which is basically room temperature. If you hold this metal it will begin to melt in your hand.
Metals Melting Temperatures Chart - but I'm not 100% about this one. It lists sterling as melting at a lower temp than fine silver and I thought you fused with fine silver because of its lower melting temp.... more research is needed?
This remarkably clear, naturally-occurring glass found in the Sahara Desert is said to have been created when a meteor hit sandstone some 28.5 million years ago. Ancient Egyptians carved it into figurines found in tombs.