Moonstone

“Take it to the Gem Sorter in the Yard: it rolls a bonus from -5% to +10% (more Agility xp), and then it goes on the Skilling side of your gem bag.”

Found while training Agility at level 60 or more: 0.017% of the actions that give Agility xp.

A gem: the Gem Sorter in the Yard rolls its bonus, and then it goes in your gem bag.

Can't be traded. Gems can't be traded. The one you find is yours; the Gem Sorter will buy it.

Type	Gem
Get it	Found while training Agility at level 60 or more: 0.017% of the actions that give Agility xp.
Trade	Can't be traded