Scandium's big claim to fame is:
The original use of scandium-aluminium alloys was in the nose cones of some USSR submarine-launched ballistic missiles (SLBMs). The strength of the resulting nose cone was enough to enable it to pierce the ice-cap without damage, and so, enabling a missile launch while still submerged under the Arctic ice cap.from Wikipedia.
But here we have a handgun (specifically a S&W 1911 sc Commander) made with a scandium alloy, scandium alloyed with aluminum, presumably. Once again something obscure has crept into my life without my previously noticing it.
From an article in Guns Magazine, Sept, 2002 by Massad Ayoob:
For carrying comfort, obviously lighter is better. An all-steel "J-frame" hammerless may weigh 20 ounces. The aluminum framed Airweight version is perhaps 14 ounces. The AirLite Ti version cuts overall weight to under 12 ounces. Scandium construction allows for a .357 Magnum AirLite Centennial that weighs barely over 10 ounces. As weight goes down, recoil goes up.