INTRINSIC CHARACTERISTICS

The ability of one mineral to scratch another brings up the story :o tell a genuine diamond by its ability to scratch or cut s true enough. Yet, as a test of diamonds it is closer to -act. The fact is that other minerals will also scratch glass. -e same approximate hardness as apatite (5). Thus, not 3monds scratch glass but all minerals with the hardness quartz, topaz, and corundum will also scratch glass. we harder the mineral, the easier it will be to do that.

Regardless of the desirability of hardness, however, it would be an oversimplification to say that hardness alone makes one gem alone than another gem. True enough, diamonds as well as rubies are the hardest gems and are desirable and expensive. Yet not all gems below 7 on the scale are all that much e and less expensive.

Jade, the "toughest" gem, is between 6'/z and 7 on the scale, n the type of jade. It is very desirable and expensive. Opals are other example. While they have only the hardness of and are fragile without the toughness of jade, opals can give and rare, as is the case with Australian black opals. Next are pearls, which rank between calcite and fluorite at 3'/z on the scale. Their relative softness does not affect their beauty nor the demend for them. Thus, the Mohs scale is not a scale of absolute desirability

Still, the scale serves several purposes as far as the consumer is concernerd, which is why the hardness of the various gems will be given next chapter. It points out:

*Care should be taken in wearing gems, especially the softer ones.

*Jewelry with gems of one kind should be stored separately from jewels of another kind to avoid the gems' scratching one another.