Once the nagas are dead, hang from the edge again and traverse towards the pillar. Jump to grab the next ledge and pull up.

Jump to grab the handhold on the pillar, then the next one above. Traverse to the right around the corner...

... and jump up twice to reach the top of the pillar.

Turn a bit to the left and jump to the stone beam. Then walk to the ledge and turn left.

Use the Grapple to catch the metal ring above and jump forward. When Lara's legs reach the wall, press Up and Interact to climb up and reach the ledge with the meachanism. Get the Gem (Shiva) #2.