The ruby is an odd gem as one side has been cut smooth, while the opposite side has the usually four to five facets. But what it does is beyond your understanding at the moment.
Having looked everywhere in what appears to be Merrin's workshop, the group realizes that the journal said the spell was buried with Iyarim, who must be the skeleton in the first room. If you think of this place as his whole tomb, than the spell could be buried anywhere down here. But no one took to checking the skeleton's person to see if the scroll was on him (or maybe in him?).
Skill challenge successful. The group knows that the spell is here and Merrin hasn't found it, from the journal entry. You all now believe it must be somewhere near or on the skeleton (who was Iyarim).
Spending a short rest with an item allows you to identify it. Requires another short rest to attune. Unclear in RAW if you can chain those (2 hours), since it's still technically one short rest. The only way RAW you can immediately identify something is with the Identify spell. DM call on how to use Arcana, but I might at least allow them to decipher the school of magic.
Zuleyka eyed the spell scrolls. Thunderclap was a bit noisy, but could be useful. She tucked it away into her pack to copy later. The other spell was barely decipherable to her, obviously not made by a wizard.
“I believe this is better for you,” the drow bladesinger said, handing the magic stone spell to Bilkar.
The little gnome jumped around excitedly and ran off back to the throne room where the bones lay.
“The little beast might just be right,” Zuleyka told Ssz’irac. “Merrim obviously didn’t find what he was looking for.”
She turned to follow Bilkar back to the throne. “Let’s see what we can find.” She started to search the throne for any secret compartments, and dig through the bones for whatever she might find.
Bilkar rushes to the front of the throne looking over the old bones, but not willing to touch them.
Zuleyka casually walks up the corridor to the throne room and allows Ssz'irac to pass her. As he does her eyes once more wonder down to his backside and calves. That is when she notices the small scraps on the floor near the black stone throne.
As Alberich nears the end of the corridor at the throne room his detect spell tells him the metal helm on one of the wooden pegs is magical.
Bilkar excitedly scurries into the throne room skidding to a stop sniffing about a foot away from the bones of the dead wizard before running off to the wall. His ear against the wall he starts knocking with his hand on various areas and listening for sounds of a hollow wall.
Bilkar is just going to keep knocking, till he finds something or someone else does. Walls, floor, throne, ceiling if he can get there somehow. From the last room he's convinced it's here and it's just a matter of finding it.
At one point, knocking on the floor he finds a spider picks it up and is about to eat it, until he sees the Drow elves also searching the room, then he puts it back down gently pats it and continues knocking and listening.
Zuleyka, distracted by Ssz’irac’s posterior -- she really needed to scratch that itch -- almost missed it, but she stopped. As Bilkar tapped the walls, she knelt down, running her long, delicate fingers along some scrapes in the stone of the floor.
“I think the throne moves,” she told the others. She glanced up at the throne. “Help me try and push this.”
Ssz'irac uses the help from Zuleyka to try and move the stone throne, and it slides slowly across the floor. The grinding sound turns everyone's head towards the moving throne. The bones clatter a moment before toppling onto the floor in a racket.
But the female drow is not perturbed as she keeps her eyes on the floor. Poor Ssz'irac has his head to the other side as he puts his shoulders into the pushing, seeing nothing. He stops and pants a bit before putting his hands on his knees and bending at the waste. "So? What did we find."
Zuleyka sees an ornate scroll case resting in the small cubby-hole dug into the floor. She reaches down smiling and lifts the case up to show everyone.
Suddenly there is a rattle of metal on stone as another flying dagger, this one hidden under the scroll case, floats up and over the throne and threatens the pair of drow warriors.
Al takes and puts a good notch into the floating dagger causing it to vibrate as if it were losing its ability to float. Then Zuleyka's rapier finishes off whatever enchantment held the thing spell bond and it clatters to the floor, still whole, but unmoving.
Bilkar comes over on all fours as the throne moves, annoyed at first as they are making too much noise for him to hear any hollow areas. Then excitement as he sees the scroll, and fear as the dagger flies up and he jumps back falling on his butt.
The pack quickly dispatches the dagger and he crawls over pulling out the scroll and examining it quickly before anything else goes wrong.