| Rating | Solver | Clue |
|---|---|---|
| OBSIDIAN | Glassy volcanic rock | |
| PEARLSTONE | A glassy volcanic rock of a grayish color and pearly luster, often having a spherulitic concretionary structure due to the curved cracks produc... | |
| IGNEOUS | Volcanic (rock) | |
| TUFF | Volcanic rock | |
| BASALT | Volcanic rock | |
| PUMICE | Porous volcanic rock | |
| LAVA | Flowing volcanic rock | |
| ANDESITE | Igneous volcanic rock | |
| MAGMA | The glassy base of an eruptive rock. | |