So Insulation Room is on a small circuit, and how you find the bone depends on the direction you're taking. Are you swimming clockwise or couterclockwise?
Without knowing the direction, the best advice I can give you this: look at the walls very carefully. There is going to be a dark / untouched space on the wall with a visible light spot and a brick sticking out of it. If you go clockwise on the circuit, the spot/bone will be on your left-ish side. Btw, unless you've seen a bone in Ginnie - there are at least 2 more - it is hard to describe it. If you're looking or hoping for something looking like a dinosaur bone, you won't find it. It is literally a black brick looking thing.
0:29 in this video:
IIRC, the spare around the bone is much lighter now, and the "brick" stands out.
