Nobody who fuses with the Gem In Black can remember it for long. So they’re constantly rediscovering what their fusion forms are.
Leaf Green Pearl (Leif) + Snowflake Obsidian = Limo o Pele, a volcanic glass formed when lava interacts with ocean waves.
Sapphire (Thorn) + Snowflake Obsidian = Blue Goldstone, a sparkly blue manmade glass.
Bloodstone (Delphinium) + Snowflake Obsidian = Helgoland Flint, a red silicate glass.