Volanite and other Volantantium Family minerals. Volantantium is often found in these mineral deposits.
Volantantium is a silvery, super-heavy metal with a bluish hue, and an oxidation number of +3. It is mildly reactive, and does not rust in air. Volantantium has a high melting point, of 1650° Celsius, and as such, it is great for making heat resistance machine parts. However, it is very tough to bend and mould, so it is usually used in alloys with lighter metals (which increases not only its malleability, but its melting point).
Iron-Voltan (Iron: 10%, Volantantium 75%, Tallium-50 15%), is often used by the Ta'Elans for creating heat shields. It has a high melting point of 3900° C, but can withstand external temperatures way past its melting point because of its low conductivity to heat. In fact, lower layers may remain solid even after outer the layers melt, because the melted outer layers provide increased insulation.