Gemstone Hardness

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Mohs' scale of mineral hardness was created by the German mineralogist Friedrich Mohs in 1822 to measure the relative hardness or scratch resistance of various minerals. He based it on ten readily available minerals. As it is an ordinal scale, you have to compare two minerals to decide which is harder. The scale is neither linear nor logarithmic. For example, corundum is twice as hard as topaz, but diamond is almost four times as hard as corundum.

The hardness of a material is measured against the scale by finding the hardest material that that the given material can scratch, or the softest material that can scratch the given material.

Mohs original scale is as follows:

Hardness	Material	Absolute Hardness
1	Talc (Mg3Si4O10(OH)2)	1
2	Gypsum (CaSO4·2H2O)	3
3	Calcite (CaCO3)	9
4	Fluorite (CaF2)	21
5	Apatite (Ca5(PO4)3(OH-,Cl-,F-))	48
6	Orthoclase (KAlSi3O8)	72
7	Quartz (SiO2)	100
8	Topaz (Al2SiO4(OH-,F-)2)	200
9	Corundum (Al2O3)	400
10	Diamond (C)	1500

To give some examples from everyday life,
a fingernail has a hardness of 2;
a copper penny, about 3;
a knife blade, 5;
window glass, 5.5;
and a steel file, 6.5.

Here are the Mohs scale ratings for 144 types of gemstones:

Gem	Hardness	Info Page
Diamond	10	Diamond Information Page
Star Sapphire	9	Star Sapphire Information Page
Color-Change Sapphire	9	Color-Change Sapphire Information Page
Star Ruby	9	Star Ruby Information Page
Ruby	9	Ruby Information Page
Sapphire	9	Sapphire Information Page
Alexandrite	8.5	Alexandrite Information Page
Chrysoberyl	8.5	Chrysoberyl Information Page
Chrysoberyl Cat's Eye	8.5	Chrysoberyl Cat's Eye Information Page
Rutile Topaz	8	Rutile Topaz Information Page
Spinel	8	Spinel Information Page
Imperial Topaz	8	Imperial Topaz Information Page
Topaz	8	Topaz Information Page
Azotic Topaz	8	Azotic Topaz Information Page
Mystic Topaz	8	Mystic Topaz Information Page
Goshenite	7.5 - 8	Goshenite Information Page
Beryl	7.5 - 8	Beryl Information Page
Morganite	7.5 - 8	Morganite Information Page
Cat's Eye Aquamarine	7.5 - 8	Cat's Eye Aquamarine Information Page
Andalusite	7.5	Andalusite Information Page
Hambergite	7.5	Hambergite Information Page
Emerald	7.5 - 8	Emerald Information Page
Aquamarine	7.5 - 8	Aquamarine Information Page
Mystic Quartz	7	Mystic Quartz Information Page
Paraiba Tourmaline	7 - 7.5	Paraiba Tourmaline Information Page
Aventurine	7	Aventurine Information Page
Danburite	7 - 7.5	Danburite Information Page
Rutile Quartz	7	Rutile Quartz Information Page
Smoky Quartz	7	Smoky Quartz Information Page
Amethyst	7	Amethyst Information Page
Citrine	7	Citrine Information Page
Ametrine	7	Ametrine Information Page
Strawberry Quartz	7	Strawberry Quartz Information Page
Quartz Cat's Eye	7	Quartz Cat's Eye Information Page
Iolite	7 - 7.5	Iolite Information Page
Demantoid Garnet	7 - 7.5	Demantoid Garnet Information Page
Tourmaline	7 - 7.5	Tourmaline Information Page
Rose Quartz	7	Rose Quartz Information Page
Kunzite	7	Kunzite Information Page
Chrome Tourmaline	7 - 7.5	Chrome Tourmaline Information Page
Dumortierite Quartz	7 - 8.5	Dumortierite Quartz Information Page
Rubellite Tourmaline	7 - 7.5	Rubellite Tourmaline Information Page
Cat's Eye Tourmaline	7 - 7.5	Cat's Eye Tourmaline Information Page
Quartz	7	Quartz Information Page
Star Lemon Quartz	7	Star Lemon Quartz Information Page
Peridot	6.5 - 7	Peridot Information Page
Spessartite Garnet	6.5 - 7.5	Spessartite Garnet Information Page
Dendritic Agate	6.5 - 7	Dendritic Agate Information Page
Peanut Wood	6.5 - 7	Peanut Wood Information Page
Onyx	6.5 - 7	Onyx Information Page
Ruby-Zoisite	6.5 - 7	Ruby Zoisite Information Page
Zircon	6.5 - 7.5	Zircon Information Page
Fossil Coral	6.5 - 7	Fossil Coral Information Page
Star Garnet	6.5 - 7.5	Star Garnet Information Page
Spodumene	6.5 - 7	Spodumene Information Page
Chalcedony	6.5 - 7	Chalcedony Information Page
Axinite	6.5 - 7	Axinite Information Page
Melanite	6.5 - 7	Melanite Information Page
Tanzanite	6.5 - 7	Tanzanite Information Page
Chrysoprase	6.5 - 7	Chrysoprase Information Page
Star Rose Quartz	6.5 - 7	Star Rose Quartz Information Page
Color-Change Diaspore	6.5 - 7	Diaspore Information Page
Tiger's Eye	6.5 - 7	Tiger's Eye Information Page
Hiddenite	6.5 - 7	Hiddenite Information Page
Almandine Garnet	6.5 - 7.5	Almandine Garnet Information Page
Cat's Eye Diaspore	6.5 - 7	Cat's Eye Diaspore Information Page
Pyrope Garnet	6.5 - 7.5	Pyrope Garnet Information Page
Agate Geode	6.5 - 7	Agate Geode Information Page
Mali Garnet	6.5 - 7.5	Mali Garnet Information Page
Tiger's Eye Matrix	6.5 - 7	Tiger's Eye Matrix Information Page
Jasper	6.5 - 7	Jasper Information Page
Grossularite Garnet	6.5 - 7.5	Grossularite Information Page
Fire Agate	6.5 - 7	Fire Agate Information Page
Color-Change Garnet	6.5 - 7.5	Color-Change Garnet Information Page
Agate	6.5 - 7	Agate Information Page
Tsavorite Garnet	6.5 - 7.5	Tsavorite Garnet Information Page
Sillimanite Cat's Eye	6.5 - 7.5	Sillimanite Cat's Eye Information Page
Hessonite Garnet	6.5 - 7.5	Hessonite Garnet Information Page
Bloodstone	6.5 - 7	Bloodstone Information Page
Carnelian	6.5 - 7	Carnelian Information Page
Rhodolite Garnet	6.5 - 7.5	Rhodolite Garnet Information Page
Idocrase	6.5	Idocrase Information Page
Orthoclase	6 - 6.5	Orthoclase Information Page
Prehnite	6 - 6.5	Prehnite Information Page
Nephrite Jade	6 - 6.5	Nephrite Jade Information Page
Sunstone	6 - 6.5	Sunstone Information Page
Andesine Labradorite	6 - 6.5	Andesine Labradorite Information Page
Rainbow Moonstone	6 - 6.5	Rainbow Moonstone Information Page
Star Sunstone	6 - 6.5	Star Sunstone Information Page
Maw-Sit-Sit	6 - 7	Maw-sit-sit Information Page
Jadeite	6 - 6.5	Nephrite Information Page
Star Moonstone	6 - 6.5	Star Moonstone Information Page
Rainbow Pyrite	6 - 6.5	Rainbow Pyrite Information Page
Amazonite	6 - 6.5	Amazonite Information Page
Clinohumite	6	Clinohumite Information Page
Labradorite	6 - 6.5	Labradorite Information Page
Cassiterite	6 - 7	Cassiterite Information Page
Moonstone	6 - 6.5	Moonstone Information Page
Kyanite	6 - 7	Kyanite Information Page
Sugilite	6 - 6.5	Sugilite Information Page
Opal Doublet	5.5 - 6.5	Opal Doublet Information Page
Sodalite	5.5 - 6	Sodalite Information Page
Hackmanite	5.5 - 6	Hackmanite Information Page
Nuumite	5.5 - 6	Nuumite Information Page
Opal	5.5 - 6.5	Opal Information Page
Moss Opal	5.5 - 6.5	Moss Opal Information Page
Rhodonite	5.5 - 6.5	Rhodonite Information Page
Boulder Opal	5.5 - 6.5	Boulder Opal Information Page
Hematite	5.5 - 6.5	Hematite Information Page
Fire Opal	5.5 - 6.5	Fire Opal Information Page
Cat's Eye Scapolite	5.5 - 6	Cat's Eye Scapolite Information Page
Scapolite	5.5 - 6	Scapolite Information Page
Moldavite	5.5	Moldavite Information Page
Sphene	5 - 5.5	Sphene Information Page
Star Diopside	5 - 6	Star Diopside Information Page
Cat's Eye Apatite	5	Cat's Eye Apatite Information Page
Apatite	5	Apatite Information Page
Snowflake Obsidian	5 - 5.5	Snowflake Obsidian Information Page
Tremolite-Hexagonite	5 - 6	Tremolite-Hexagonite Information Page
Tashmarine Diopside	5 - 6	Tashmarine Diopside Information Page
Smithsonite	5	Smithsonite Information Page
Lapis Lazuli	5 - 6	Lapis Lazuli Information Page
Obsidian	5 - 5.5	Obsidian Information Page
Hemimorphite	5	Hemimorphite Information Page
Turquoise	5 - 6	Turquoise Information Page
Chrome Diopside	5 - 6	Diopside Information Page
Charoite	4.5 - 5	Charoite Information Page
Larimar	4.5 - 5	Larimar Information Page
Gaspeite	4.5 - 5	Gaspeite Information Page
Fluorite	4	Fluorite Information Page
Rhodochrosite	4	Rhodoschrosite Information Page
Ammolite	4	Ammolite Information Page
Variscite	4 - 5	Variscite Information Page
Malachite	3.5 - 4	Malachite Information Page
Sphalerite	3.5 - 4	Sphalerite Information Page
Azurite	3.5 - 4	Azurite Information Page
Coral	3 - 4	Coral Information Page
Verdite	3	Verdite Information Page
Calcite	3	Calcite Information Page
Lepidolite	2.5 - 3	Lepidolite Information Page
Pearl	2.5 - 4.5	Pearl Information Page
Seraphinite	2 - 4	Seraphinite Information Page
Amber	2 - 2.5	Amber Information Page
Chrysocolla	2 - 4	Chrysocolla Information Page

First Published: September-16-2006

© 2005-2013 GemSelect.com all rights reserved.
Reproduction (text or graphics) without the express written consent of GemSelect.com (SETT Company Ltd.) is strictly prohibited.

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ID: 3376232 pcs

9.00mm

US $102.71

ID: 3500191 pc

Spinel Gemstone

7.44 x 5.55 x 3.26mm

US $98.10

ID: 2877131 pc

8.93 x 5.09mm

US $18.59

ID: 3337442 pcs

Rutile Quartz Gemstone

13.87ctw Rutile Quartz

12.25 x 10.16 x 7.14mm

US $48.54

ID: 33739620 pcs

Labradorite Gemstone

7.48ctw Labradorite

4.75 x 2.93mm

US $14.96

ID: 2839881 pc

7.46 x 7.27 x 4.15mm

US $12.08

ID: 3207694 pcs

Tourmaline Gemstone

2.2ctw Tourmaline

6.03 x 3.67mm

US $39.60

ID: 3236041 pc

6.24 x 6.20 x 4.62mm

US $9.08

ID: 2831494 pcs

Sapphire Gemstone

2.79ctw Sapphire

4.48 x 4.48 x 3.42mm

US $102.53

ID: 3169935 pcs

Sapphire Gemstone

2.89ctw Sapphire

5.94 x 4.08 x 2.68mm

US $394.49

ID: 3392986 pcs

7.07 x 3.62 x 2.23mm

US $17.86

Customer Reviews

Good purchasing online thus far, will see when the item gets here about the quality of the item purchased

Online Shopper, March, 2013
Source: Bizrate

Excellent. Items were gorgeous and exactly as pictured. Ordered on Monday, rec'd. Thursday AM !! I liked the website and the details of the items. It was an easy, fast and clean transaction. Admitting here that I have purchased from GemsTV and found that some gems ordered were less than advertised. Now I am happy that I can see an exact picture of the item I am to receive.

Online Shopper, October, 2011
Source: ReviewCenter

Good with the service :)

Online Shopper, August, 2012
Source: ReviewCenter

There is a good selection of sizes and colors

Online Shopper, May, 2013
Source: Bizrate

I have ordered several gems from Gemselect and I am very pleased with both the price and the quality. The gems are perfect in every way. I took one gem topaz london blue and the server couldn't believe the color, and the cut of the gem. He thought I paid a lot of money for the gem. I didn't say how much I paid, but he was very impressed. I felt proud that I was holding in my hand a very special gem. It made me realize just how much profit jewellery stores are making. Gemselect gems are...

gemsformary, October, 2012
Source: ReviewCenter

Very fast shipping from Thailand to Conus. Gems were as advertised. Compared to some other the other gem dealers on the web I've dealt with Gem Select are very professional. Will definitely do more business with this proprietor.

Online Shopper, January, 2009
Source: ReviewCenter