Genseki Wakusei (幻石惑星)

Overview
Genseki Wakusei (幻石惑星, Gem Planet) is a Japanese Yume Nikki Fangame by TOM, developer of nostAlgic.

Gameplay
You play as a girl named Pershina (ペルシナ) in a small spherical room with no doors or other details outside of a big crystal gem. This is the only place you can open the menu screen to save the game. Interacting with the big crystal gem warps Pershina to the Nexus, the 4 edges of the screen acting as warps to dream worlds.

Effects
In this game the effects are called "Stones" (いし).