The Treasure Trove's overall design is modeled after the crystal mines in the Dwarf Woodlands. Its appearance varies depending on its upgrades, most of which appear in Kingdom Hearts χ.
The default Treasure Trove has a circular guard with a yellow crystal on the pommel. The base of the blade is a dull brown minecart that contains rocks and a stick, with the blade itself being a track with two planks. A disjointed pickaxe, with one of its spikes being noticeably shorter than the other, serves as the teeth, and the Keychain displays a green crystal.
The first upgrade features a number of changes to the design. There are now three planks on the blade, and three silver crystals adorn the guard. The cart now boasts a silver coloration and a gold crystal among the rocks inside it, and a cyan crystal is now on the Keychain. The pickaxe still has one spike shorter than the other.
The second upgrade, also seen in Kingdom Hearts Birth by Sleep, has seven crystals on the guard, three white, two yellow, and two blue. The minecart is filled to the brim with crystals in various shades of blue and yellow. The blade is made up of a short mine track with four crooked planks nailed onto it. The pickaxe's spikes are even. The Keychain displays a red jewel.
The third upgrade features silvery-grey tracks on the blade, with four silver planks adorned with sparkle effects. The cart takes on a brightly silver look with gold wheels and is heaped with gold and blue crystals. The guard is now adorned with violet, pearl, and blue crystals all around, and the Keychain is now silver with a gold crystal as the token. The pickaxe now sports a silver head and grey handle.
The fourth upgrade has the guard decorated with silver and gold crystals. The cart is now black with silver wheels, and the crystals tower over the top, in shades of yellow, blue, grey and red, with one grey crystal flying off the top of the pile. The blade features golden rails and planks, and the Keychain is grey with a red crystal. The pickaxe is still silver. The crystals, rails, pickaxe and Keychain token are all decorated with sparkle effects.
The fifth upgrade gives the Keyblade a powerful, swirling yellow aura.
A "treasure trove" is a phrase that refers to finding a hidden treasure, which reflects the gems the Seven Dwarfs mine. The Keyblade's Japanese name holds a similar meaning, with "splendor" meaning "great luster or brilliance". The full name, "Rock Splendor", references the luster of gemstones.