Respuesta :

lilbrother867

Answer:

5.5 to 7 Mohs

Explanation:

Glass ranks around 5.5 to 7 Mohs, but sapphire crystal has a hardness of 9 Mohs, making it only slightly less hard than diamond.

colaciwilliam

Answer: 5.5

Explanation:

Several hardness scales have been developed to catalog the materials (specifical minerals), being the Mohs scale the best known. This scale, proposed by the German geologist Friedrich Mohs in 1825, consists of a ratio of ten minerals numbered in increasing order by hardness, from least to greatest.