From the top of the rock, jump to spire #1 and then to spire #2. Jump to SPIRE #A then jump back to spire #2. From there, jump to SPIRE #B and again back to spire #2.

Jump to spires #3 and #4, then to SPIRE #C. Before it sinks, jump to spire #5.

Jump to SPIRE #D, let it sink a bit and jump to spire #6. If you jump before SPIRE #D sinks a bit, Lara will jump high enough and bypass spire #6. In this case, she will slide down, but it is not a big deal. Just make your way to spire #6 again.

Jump to spires #7 and #8 and then to SPIRE #E. Before it sinks, jump back to spire #8.

For the Artifact, jump to SPIRE #F and, before it sinks, quickly jump to grab the crevice of the rock beyond. Traverse around and climb to the top. After getting the Artifact, jump to spire #8 and head to the alcove.

If SPIRE #F sinks before you jump/ grab the crevice, you cannot get the Artifact and you have to load a saved game.