Hukukutu (hardness in English) zvinoreva kuti chinhu chakasimba zvokuti hachimarike zviri nyore. Diamond inozivikanwa nokuva nehukukutu zvokuti hakuna chimwe chinokwanisa kuimara. Nokudaro diamond inoshandoswa pama drill anoshandiswa kucheka dombo pasi pemugodhi.
Kukukutara (be hard).
Gukuta (dry skin) zvichireva ganda rakawoma. Gukuta izita remhuri.