WHAT IS THE MOHS SCALE?

The Mohs Scale of Hardness is a scale that lists the Hardness of Minerals from weakest to strongest.

The Mohs Scale was developed in 1812 by a German Mineralogist named Friedrich Mohs. Mohs came up with a main list of Ten Natural Minerals to show their hardness and scratch resistance to each other.

While most of these items on the list are in some what of a relative order, the last one, Diamond, is an exception! Diamond is 4 times harder than Corundum.

The Mohs Scale of Hardness is as follows:

1 -	TALC - 1
2 -	GYPSUM - 2
3 -	CALCITE - 9
4 -	FLUORITE - 21
5 -	APATITE - 48
6 -	FELDSPAR - 72
7 -	QUARTZ - 100
8 -	TOPAZ - 200
9 -	CORUNDUM - 400
10 -	DIAMOND - 1600 (Red numbers are Absolute Hardness)

Comparing these items on the Mohs Scale, you'll see that there are interesting red numbers after the names. Those numbers are the Mineral's "Absolute Hardness". That number is what the hardness of the Mineral truly is. Mohs just put them on a scale of 1 to 10 to simplify things and make it easier for people to relate. But as you can see, Diamond is a huge leap above and beyond the entire rest of the list.

The Mohs Scale is certainly a much more detailed list than just ten items. Where do the rest of the Gemstones, Rocks, Minerals and Common things fall in line? Where do they compare on the Mohs Scale? What about common house-hold items? Let's find out. Below is a giant list of items compiled together to form the biggest Mohs Scale list on the net. This is what I call the Extended Mohs Scale list! It's huge & fascinating! The Complete Mohs Scale list is:

Plastic - 1 Graphite - 1 Talc - 1 Pencil Lead - 1 Sulfur - 1.5 - 2.5 Gypsum - 2 Alabaster - 2 Rock Salts - 2 Plaster of Paris - 2 Mercury - 2 - 2.5 Salt - 2 - 3 Amber - 2.5 Ivory - 2.5 Fingernail - 2.5 Pearl - 2.5 Zinc - 2.5 Gold - 2.5 - 3 Silver - 2.5 - 3 Aluminum - 2.5 - 3 Jet - 2.5 - 3 Copper Penny - 3 Calcite - 3 Limestone - 3 Shells - 3 Bronze - 3 Coral - 3 Barite - 3 - 3.5 Malachite - 3.5 - 4 Azurite - 3.5 - 4 Fluorite - 4 Platinum - 4 - 4.5 Iron - 4 - 5 Meteorite - 4.5 Palladium - 4.75 Apatite - 5 Tooth Enamel - 5

Lapis - 5 - 5.5 Obsidian - 5 - 5.5 Hematite - 5 - 6 Knife Blade - 5.5 Opal - 5.5 - 6 Turquoise - 5.5 - 6 Magnetite - 5.5 - 6.5 Rhodonite - 5.5 - 6.5 Titanium - 6 Rhodium - 6 Feldspar - 6 Orthoclase - 6 Rutile - 6 - 6.5 Fire Opal - 6 - 6.5 Moonstone - 6 - 6.5 Marcasite - 6 - 6.5 Iron Pyrite - 6.5 Tanzanite - 6.5 Nephrite - 6 - 7 Jade - 6 - 7 Glass - 6 - 7 Cassiterite - 6 - 7 Iridium - 6.5 Kunzite - 6.5 - 7 Peridot - 6.5 - 7 Bloodstone - 7 Quartz - 7 Rose Quartz - 7 Smokey Quartz - 7 Milk Quartz - 7 Black Opal - 7 Flint - 7 Aventurine - 7 Ametrine - 7 Agate - 7 Chalcedony - 7

Citrine - 7 Jasper - 7 Onyx - 7 Carnelian - 7 Amethyst - 7 Tiger's Eye - 7 Garnet - 7 - 7.5 Rhodolite - 7 - 7.5 Iolite - 7 - 7.5 Tourmaline - 7 - 7.5 Steel File - 7 - 8 Zircon - 7.5 Tungsten - 7.5 Morganite - 7 - 8 Beryl - 7.5 - 8 Aquamarine - 7.5 - 8 Emerald - 7.5 - 8 Spinel - 8 Topaz - 8 Smokey Topaz - 8 Blue Topaz - 8 Yellow Topaz - 8 Chrysoberyl - 8.5 Alexandrite - 8.5 Cat's Eye - 8.5 Cubic Zirconia - 8.5 Chromium - 8.5 Tungsten Carbide - 8.5 - 9 Corundum - 9 Sapphire - 9 Ruby - 9 Carborundum - 9 - 9.5 Moissanite - 9.25 Fullerite - 10- Diamond - 10 Nanorods - 10+

What all this really means, is that any item on the Mohs Scale list, can scratch any item below it on the Scale. Hence, a Fingernail (2.5) can scratch Plaster of Paris (2 ). A Penny (3) can scratch a Pearl (2.5). And Platinum (4 - 4.5) can scratch Gold (2.5 - 3). (Which is why you shouldn't wear them side by side!) Another interesting thing about this list is Corundum (9). Corundum (or Sapphire in this instance) is what most Fine Watches use for their Crystal Face. Sapphire Crystals are great because they are so high up the scratch resistant list, very little can scratch them! (Cheaper Watches use Glass (6 - 7) or Plastic (1) as the Crystal!)

So you see, when comparing Natural Substances to each other, Diamond is the King! Diamond is the hardest known substance on the face of the Earth.

But when it comes to combining minerals with each other in the laboratory, Scientists can actually come up with new man-made synthetic minerals (like Aggregated Diamond Nanorods - 10+) that are harder and more durable than a Diamond. So while a Diamond may rule in Nature, the Labs have got the Diamond beat!

Read more about Diamond Hardness in my last blog "Do Diamonds Cut Glass?" It's an interesting blog that may surprise you!

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