The 317 isn't one of the Scandium models, but it IS one of the AirLite series revolvers, and it's also super-light like the Scandium guns, so I can understand your confusion. I once owned a 2-inch fixed sight (now gone) and currently have a 3-inch adjustable-sight 317.
It has an aluminum frame, aluminum cylinder, and an aluminum barrel shroud surrounding the rifled stainless steel barrel liner. It is VERY light, and because of that, is a challenge to shoot accurately (it is very easily moved off-target by a moderate breeze, any slight hand/arm/body movement, or a non-smooth trigger squeeze; it just has no mass/inertia to resist any inadvertent motions).
It's REALLY handy as a trail/hiking gun; it's so light, you can forget you have it on your belt. Add a pouch of ammo, and you have a great "kit" gun, if you can shoot it well enough to accomplish the task at hand.
Here's a link to photo of my 317 in the HandGunForum.net Photo Gallery:
And here's another photo of it I have hosted on the www: