gold, obsidian, ruby, muscovite, fire opal, garnet, smoky quartz
“Hephaestus is the god of fire, especially in so far as it manifests itself as a power of physical nature in volcanic districts, and in so far as it is the indispensable means in arts and manufactures, whence fire is called the breath of Hephaestus, and the name of the god is used both by Greek and Roman poets as synonymous with fire. As a flame arises out of a little spark, so the god of fire was delicate and weakly from his birth, for which reason he was so much disliked by his mother, that she wished to get rid of him, and dropped him from Olympus.” – theoi.com