| Rating | Solver | Clue |
|---|---|---|
| ARCH | Curved structure | |
| DOME | Curved structure | |
| ARGENTINE | A siliceous variety of calcite, or carbonate of lime, having a silvery-white, pearly luster, and a waving or curved lamellar structure. | |
| PEARLSTONE | ...rly luster, often having a spherulitic concretionary structure due to the curved cracks produced by contraction in cooling. See Illust. under ... |