| MOHS | Scale expressing the hardness of solids (4) |
| MOHSSCALE | A set of numbers for expressing the hardness of solids (4,5) |
| BRINELLTEST | A method of assessing the hardness of a substance (7,4) |
| TALC | It has a hardness of 1 on the Mohs scale (4) |
| TEMPER | To improve the hardness of a steel hook (6) |
| LEMONSQUEEZER | Shopper who tests the hardness of these fruit to be suitable for gadget at home (5-8) |
| OKTA | What meteorological unit is used in expressing the extent of cloud cover? (4) |
| GRAY | Old Etonian and Cantabrigian whose anonymous elegy written in, and expressing the evening mood of, an English churchyard in Stoke Poges achieved instantaneous success on its publication in 1751 (4) |
| NEPER | Non-SI unit expressing the ratio of two currents or voltages, equal to the natural logarithm of the ratio of the two quantities (5) |
| CRYSTALLOGRAPHER | Specialist in the study of solids with Unit Cells repeated in exactly the same arrangement (16) |
| TEMPERED | Of steel, improved the hardness by reheating and cooling (8) |
| DIFFICULTY | The hardness is a source of worry (10) |
| IDEOGRAM | Symbol representing the idea of a thing without expressing the name of it, such as in the Japanese writing system kanji (8) |
| SOFTEN | Point frequently and it will reduce the hardness |
| MIGNONETTE | Expressing the diminutive of French for "darling", "dainty" or "small and sweet", a plant in the genus Reseda with spires of fragrant chartreuse or white flowers; fine pillow lace; or, a sauce for fre |
| EDITORIAL | Article expressing the views of the publication (9) |
| DECIBEL | Unit of measurement expressing the intensity of a sound (7) |
| RICHTER | A scale for expressing the magnitude of an earthquake (7) |
| STEEL | Various alloys of iron and carbon with other elements increasing in strength and malleability / hardness of character |
| YORKSHIREGRIT | Hardness of some northerners who won't be ground down? (9,4) |
