Dureza

n. harshness, hardness, toughness

n. hardiness, hardness; severity

= hardness, harshness, ruggedness.
Ex: Hardness and the penetration of the ink layer into the paper were also measured = También se midió la solidez y la penetración de la tinta en el papel.
Ex: Ghobadi does not flinch from confronting the harshness of daily life in Iran in this portrayal of a small village high in the mountains.
Ex: In the 10-year gap between the publication of her first book and her second, she stretched her imagination to match the diversity and ruggedness of America.
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* con dureza = harshly.

Hardness

Johan August Brinell (1849 - 1925), swedish metallurgist who invented the Brinell hardness test

Brinell hardness

Mohs Scale of Mineral Hardness