Elkahia journal / Understanding specifications
Hardness is only one property
Resistance to scratching does not tell the whole story.
Mohs hardness describes resistance to scratching. It is an ordinal scale, so its numbers should not be read as a linear measurement. Crystal structure, cleavage and fracture behaviour supply other important parts of a mineral’s physical description.
Diamond has a Mohs hardness of 10, yet it has cleavage directions and can break. Beryl has a lower hardness and is described as brittle. These examples show why a single hardness number cannot establish whether a gem will survive every kind of impact.
Reference properties describe a mineral or a range reported for it. They do not certify the identity, treatment, origin or condition of an individual stone. Those questions need appropriate examination and, where relevant, a laboratory report.