Modifiers matching rock:

• hard,
• indigenous,
• refractory,
• reflective,
• sedimentary,
• igneous,
• vitreous,
• intermediate,
• solid,
• suitable,
• metamorphic,
• tough,
• volcanic,
• coloured,
• lightweight,
• alkaline,
• noble,
• flinty,
• strong,
• aluminous,
• fragmented,
• plutonic,
• resistant,
• crystalline,
• hot,
• covered,
• weak,
• elastic,
• dated,
• natural,
• soft,
• smaller,
• crustal,
• spherical,
• porous,
• unconsolidated,
• flat,
• impenetrable,
• sticky,
• sharp,
• fragile,
• size,
• nonporous,
• stable,
• isolated,
• polycrystalline,
• simple,
• geologic,
• common,
• refractive,
• opaque,
• anisotropic,
• molten,
• widespread,
• glassy,
• homogeneous,
• difficult,
• local,
• marine,
• original,
• extraterrestrial,
• coarse,
• inert,
• heavy,
• light,
• crumbly,
• virgin,
• free,
• terrestrial,
• new,
• argillaceous,
• impervious,
• siliceous,
• useful,
• modern,
• fine,
• calcareous,
• colorful,
• metallic,
• rich,
• smooth,
• carbonaceous,
• durable,
• ordinary,
• heavier,
• eruptive,
• barren,
• extrusive,
• chemical,
• lighter,
• organic,
• uniform,
• large,
• abrasive,
• native,
• magnetic,
• artificial,
• colored,
• british,
• visible,
• ornamental,
• inappropriate,
• unusual,
• small,
• heterogeneous,
• older,
• planetary,
• powdered,
• abundant,
• polished,
• deleterious,
• non-porous,
• white,
• surrounding,
• sedentary,
• stronger,
• compact,
• conductive,
• good,
• frozen,
• subsurface,
• textured,
• dark,
• acidic,
• brittle,
• dry,
• red,
• competent,
• permeable,
• tight,
• intrusive,
• clastic,
• angular,
• azonic,
• looking,
• rigid,
• softer,
• soluble,
• normal,
• crushed,
• korean,
• bituminous,
• related,
• unstable,
• firm,
• reactive,
• insoluble,
• loose,
• precious,
• polyphase,
• geological,
• exotic,
• weaker,
• impermeable,
• combustible,
• dense,
• enough,
• flying,
• salt,
• hardest,
• granular,
• friable,
• pulverized,
• primary,
• traditional,
• basic,
• consolidated,
• acid,
• massive,
• decorative,
• base,
• available,
• ductile,
• russian,
• typical,
• heated,
• harder,
• underlying,
• rough,
• ingenious,
• industrial,
• egyptian,

Simple categories matching tough:

• herb,
• stain,
• shrub,
• fibre,
• material,
• appendage,
• wood,
• polymer,
• fruit,
• surface,
• substance,
• contaminant,
• grass,
• food,
• group,
• stone,
• stuff,
• metal,
• job,
• exercise,
• vegetable,
• plastic,
• thing,
• condition,
• tissue,
• fish,
• tile,
• area,
• state,
• part,
• perennial,
• soil,
• plant,
• subject,
• location,
• issue,
• toy,
• meat,
• sheet,
• coating,
• times,
• fiber,
• topic,
• paper,
• bronze,
• item,
• industry,
• junk,
• decision,
• rock,
• residue,
• substrate,
• textile,
• leaf,
• hardwood,
• veggie,
• solid,
• iron,
• situation,
• workwear,
• fabric,
• application,
• alloy,
• annual,
• structure,
• resin,
• vine,
• case,
• hide,
• animal,
• spice,
• seed,
• object,