This glow is what you get when one of your characters manages a perception check - something is up with this rock! I vaguely recall this one at the bottom of a climb:
It is nothing important, just a little extra loot.
Some objects in the game can be moved to reveal more interesting things underneath them. You can drag & drop the object to a nearby location or have a character toss it - strength stat might matter. Higher tier spells like Telekinesis probably work too.
If you have no strong enough character in the party you could gamble and try something like a potion of giant strength, hoping whatever is underneath the rock is more valuable than the potion itself.