Here are some information from Cabal SEA EP9 Patch notes

1. Classified as 3 grades; Medium / High / Highest

Types and grades of equipment

2. The item becomes unbinding if using the stone is success, but it will destroy when using it fails

- Success rate depends on the enhanced level
– Success rate of +0 item is 30%, every 4% of success rate goes up by +1 enhancing

3. Enable to get from unbinding stone cube which can make by craft requesting

- Craft requesting of unbinding stone cube

- Gem of Liberation is enable to get from dungeons

4. Enable to get ‘Arcane Golems’s Unbinding Stone’ from the monsters that Arcane Golem of Rage is summoned

- Only can use to the item that enhanced level is above +10
– The item becomes unbinding if using the stone is success, but 1 enhanced level will decrease when using it fails

Here are some Extra information from me :D

There are 2 types of stone : Requested Stone & Arcane Golem’s Stone

- Requested Stone : Obtained via Requesting with NPC Chloe, when using this stone fail on item, your item will be DESTROYED
- Arcane Golem’s Stone : Obtained from minions of Arcane Golem of Rage, when using this fail on item, your upgrade level of your item will be decreased (ex was +12, used fail -> +11)

Below is the screenshot of Arcane Golem’s Unbinding Stone (High) and some facts about Unbinding Stone (Both from requested and from Arcane Golem’s minions)