The Emerald Glass Hand is an item that can be sold to the Museum for 40,000 Coins. It can be made with Level 39 Crafting with 20 Glass and an Emerald. Because an Emerald can be sold the NPC Shop for 25,000 coins, which is also the Minimum Price on the Player Market, you can gain a one-time additional 15,000 Coins from the Emerald by making the Emerald Glass Hand.
After adding the Emerald Glass Hand to the Museum, it can be examined to show the following message:
The hand shines brightly as you observe it from different angles.