G�st�e Hardn�s

Ag�eMohs Hardness: 7

���dr�eMohs Hardness: 8.5

Amaz��eMohs Hardness: 6-6.5

Am�rMohs Hardness: 2-2.5

Am�hystMohs Hardness: 7

Ap��eMohs Hardness: 5

Aqu�ar�eMohs Hardness: 7.5-8

Chal�d�yMohs Hardness: 7

Chry�pra�Mohs Hardness: 7

C�r�eMohs Hardness: 7

Using the Mohs Scale of Hardness

Di��dMohs Hardness: 10

EmeraldMohs Hardness: 7.5-8

��r�eMohs Hardness: 4

Gr�n Am�hyst (Pra ol�e)Mohs Hardness: 7

Iol�eMohs Hardness: 7-7.5

JasperMohs Hardness: 7

K�z�eMohs Hardness: 6.5-7

Ky��eMohs Hardness: 4.5-5

Labrad��eMohs Hardness: 6-6.5

LararMohs Hardness: 4.5-5

Malach�eMohs Hardness: 3.5-4

Mo�st�eMohs Hardness: 6-6.5

M�g��eMohs Hardness: 7.5-8

OpalMohs Hardness: 5.5-6

PearlMohs Hardness: 2.5

PeridMohs Hardness: 6.5-7

Prehn�eMohs Hardness: 6-6.5

Rhodochr��eMohs Hardness: 3.5-4

Rhod��eMohs Hardness: 5.5-6.5

Rhodol�e Garn�Mohs Hardness: 7-7.5

R�e QuartzMohs Hardness: 7

Ru�Mohs Hardness: 9

Sa�hireMohs Hardness: 9

Smoky QuartzMohs Hardness: 7

Sp�elMohs Hardness: 8

S�st�eMohs Hardness: 6-6.5

T�z��eMohs Hardness: 6-7

T�rmal�eMohs Hardness: 7-7.5

Turquo eMohs Hardness: 5-6

T�rmal��ed QuartzMohs Hardness: 7

T�azMohs Hardness: 8

Zirc�Mohs Hardness: 6.5-7.5

T� Mohs ScaleThe Mohs Scale of Hardness is a list of 10 minerals in order of hardness from 1 - 10 with 1 being the softest and 10 the hardest. Every mineral fits somewhere in this list. Minerals higher on the list will scratch minerals lower down. The list is a non-linear scale however: The difference in hardness between 8 (topaz) and 9 (corrundum) is actually much smaller than the difference between corrundum and diamond which holds the top spot at number 10.

1. Talc2. Gypsum3. Calcite4. Flourite5. Apatite6. Orthoclase Feldspar7. Quartz8. Topaz9. Corrundum10. Diamond

Be Aware of Tre�ed St��Glass Filled Rubies Especially!

The subject of gemstone treatments is huge! Too huge to go into here. But one treatment I do want to warn you about is glass filling which is very common in lower quality sapphires and

rubies. Be aware that the treatment used for these gemstones leaves the stone with two differ-ent hardnesses; the hardness of the stone itself and the hardness of the much softer filling

material.

Just Becau� a G�st�e Hard Do� N Me� �’s UnbreakaableA Gem’s Toughness is Also Important

Diamond is the hardest natrual mineral on the planet, but that doesn’t mean you can’t chip it. Hardness is a materials resistance to scratching only. Despite diamond being many times harder than steel, if you were to take a hammer to a diamond, you would destroy it! Be

warned, and be careful with those setting punches :)

A F� Very Imp�t�t N�Silic� Carbide - Mohs Hardn�s 9-9.5What the hell is silicon carbide and why do I care?Silicon carbide is in many abrasives including; sandpaper, rubber wheels, satin finishing wheels, 3M radial wheels and pretty much every Jool Tool accessory. What that means.... well if you touch any gemstone other than diamond with any abrasive finishing product containing this, you’ll most likely scratch it (especially with coarse grits).

P�i� - Mohs Hardn�s 6Pumice is a much safer abrasive to use around gemstones

Instead of the standard silicon carbide, pumice wheels use pumice as the abrasive. Pumice has a hardness of 6 on the Mohs scale which is harder than most metals but softer than many gemstones. Pumice wheels shouldn’t scratch gemstones rated 6.5 and above on the Mohs scale - but still use them carefully.

Fa��ed St�� N�d Extra CareIt’s possible (but not ideal) to polish cabochons when set

It’s virtually impossible to repolish facetted stones to their original condition once set. What that means.... be careful not to touch any stones with abrasives, and treat facetted stones like

your life depends on it!

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