| Answer | Crossword Clue |
|---|---|
| phonolites | A fine-grained volcanic rock composed of alkali feldspars and nepheline |
| phonolite | A fine-grained volcanic rock composed of alkali feldspars and nepheline |
| tinguaite | a fine-grained igneous rock composed essentially of feldspar, nepheline and aegirine |
| tinguaites | TINGUAITE, a fine-grained igneous rock composed essentially of feldspar, nepheline and aegirine |
| limburgite | a volcanic rock composed of olivine and augite in a fine-grained or glassy groundmass |
| limburgites | LIMBURGITE, a volcanic rock composed of olivine and augite in a fine-grained or glassy groundmass |
