I just realised that my frame material is SC7 scandium. What does that term mean? Is it aluminium alloyed with other elements?
Yes. Scandium is an element with atomic number 21. It is rare with the annual worldwide production being 15-20 tonnes total, so the pure metal commands a price of over $140 USD/gram, and Scandium Oxide is about $5 USD/gram in 2019. All of that is from https://en.wikipedia.org/wiki/Scandium
Your bike frame is not made from scandium. Instead it is an aluminium frame with traces of other additives. SC7 is a specific blend/ratio mix of those additives, to enhance lightness and reduce the downsides of aluminium in a frame.