Gemstone Hardness

Loose Gemstones:

Specials Product:
CODE: D001

Diamond Rough
0.3 - 1.5 carat
USD $ 190/Crt
Detail report
CODE: Z001

Emerald Rough
1.5 - 10 carat
USD $ 40/Crt
Detail report
CODE: R001

Ruby Rough
1.5 - 10 carat
USD $ 40/Crt
Detail report
CODE: S001

Sapphire Rough
1.5 - 10 carat
USD $ 40/Crt
Detail report
CODE: Y001

Yellow Sapphire Rough
1.5 - 10 carat
USD $ 40/Crt
Detail report
CODE:  C001

Cat Eyes Rough
1.5 - 10 carat
USD $ 30/Crt
Detail report

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Gemstone Hardness

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

Sapphire

9

Sapphire Information Page

Star Ruby

9

Star Ruby Information Page

Star Sapphire

9

Star Sapphire Information Page

Color-Change Sapphire

9

Color-Change Sapphire Information Page

Ruby

9

Ruby Information Page

Chrysoberyl

8.5

Chrysoberyl Information Page

Chrysoberyl Cat’s Eye

8.5

Chrysoberyl Cat’s Eye Information Page

Alexandrite

8.5

Alexandrite Information Page

Azotic Topaz

8

Azotic Topaz Information Page

Rutile Topaz

8

Rutile Topaz Information Page

Mystic Topaz

8

Mystic Topaz Information Page

Spinel

8

Spinel Information Page

Imperial Topaz

8

Imperial Topaz Information Page

Topaz

8

Topaz Information Page

Beryl

7.5 - 8

Beryl Information Page

Hambergite

7.5

Hambergite Information Page

Goshenite

7.5 - 8

Goshenite Information Page

Morganite

7.5 - 8

Morganite Information Page

Emerald

7.5 - 8

Emerald Information Page

Cat’s Eye Aquamarine

7.5 - 8

Cat’s Eye Aquamarine Information Page

Andalusite

7.5

Andalusite Information Page

Aquamarine

7.5 - 8

Aquamarine Information Page

Rose Quartz

7

Rose Quartz Information Page

Citrine

7

Citrine Information Page

Ametrine

7

Ametrine Information Page

Mystic Quartz

7

Mystic Quartz Information Page

Paraiba Tourmaline

7 - 7.5

Paraiba Tourmaline Information Page

Strawberry Quartz

7

Strawberry Quartz Information Page

Quartz Cat’s Eye

7

Quartz Cat’s Eye Information Page

Kunzite

7

Kunzite Information Page

Aventurine

7

Aventurine Information Page

Rutile Quartz

7

Rutile Quartz Information Page

Chrome Tourmaline

7 - 7.5

Chrome Tourmaline Information Page

Iolite

7 - 7.5

Iolite Information Page

Danburite

7 - 7.5

Danburite Information Page

Smoky Quartz

7

Smoky Quartz Information Page

Rubellite Tourmaline

7 - 7.5

Rubellite Tourmaline Information Page

Demantoid Garnet

7 - 7.5

Demantoid Garnet Information Page

Amethyst

7

Amethyst Information Page

Cat’s Eye Tourmaline

7 - 7.5

Cat’s Eye Tourmaline Information Page

Quartz

7

Quartz Information Page

Tourmaline

7 - 7.5

Tourmaline Information Page

Dumortierite Quartz

7 - 8.5

Dumortierite Quartz Information Page

Star Lemon Quartz

7

Star Lemon Quartz Information Page

Mali Garnet

6.5 - 7.5

Mali Garnet Information Page

Axinite

6.5 - 7

Axinite Information Page

Idocrase

6.5

Idocrase Information Page

Melanite

6.5 - 7

Melanite Information Page

Tanzanite

6.5 - 7

Tanzanite Information Page

Tiger’s Eye Matrix

6.5 - 7

Tiger’s Eye Matrix Information Page

Peridot

6.5 - 7

Peridot Information Page

Jasper

6.5 - 7

Jasper Information Page

Chrysoprase

6.5 - 7

Chrysoprase Information Page

Dendritic Agate

6.5 - 7

Dendritic Agate Information Page

Spessartite Garnet

6.5 - 7.5

Spessartite Garnet Information Page

Fire Agate

6.5 - 7

Fire Agate Information Page

Grossularite Garnet

6.5 - 7.5

Grossularite Information Page

Star Rose Quartz

6.5 - 7

Star Rose Quartz Information Page

Color-Change Garnet

6.5 - 7.5

Color-Change Garnet Information Page

Agate

6.5 - 7

Agate Information Page

Color-Change Diaspore

6.5 - 7

Diaspore Information Page

Tsavorite Garnet

6.5 - 7.5

Tsavorite Garnet Information Page

Onyx

6.5 - 7

Onyx Information Page

Peanut Wood

6.5 - 7

Peanut Wood Information Page

Tiger’s Eye

6.5 - 7

Tiger’s Eye Information Page

Sillimanite Cat’s Eye

6.5 - 7.5

Sillimanite Cat’s Eye Information Page

Ruby-Zoisite

6.5 - 7

Ruby Zoisite Information Page

Hiddenite

6.5 - 7

Hiddenite Information Page

Zircon

6.5 - 7.5

Zircon Information Page

Bloodstone

6.5 - 7

Bloodstone Information Page

Hessonite Garnet

6.5 - 7.5

Hessonite Garnet Information Page

Cat’s Eye Diaspore

6.5 - 7

Cat’s Eye Diaspore Information Page

Almandine Garnet

6.5 - 7.5

Almandine Garnet Information Page

Carnelian

6.5 - 7

Carnelian Information Page

Pyrope Garnet

6.5 - 7.5

Pyrope Garnet Information Page

Fossil Coral

6.5 - 7

Fossil Coral Information Page

Spodumene

6.5 - 7

Spodumene Information Page

Agate Geode

6.5 - 7

Agate Geode Information Page

Star Garnet

6.5 - 7.5

Star Garnet Information Page

Chalcedony

6.5 - 7

Chalcedony Information Page

Rhodolite Garnet

6.5 - 7.5

Rhodolite Garnet Information Page

Rainbow Pyrite

6 - 6.5

Rainbow Pyrite Information Page

Orthoclase

6 - 6.5

Orthoclase Information Page

Amazonite

6 - 6.5

Amazonite Information Page

Sugilite

6 - 6.5

Sugilite Information Page

Star Sunstone

6 - 6.5

Star Sunstone Information Page

Clinohumite

6

Clinohumite Information Page

Prehnite

6 - 6.5

Prehnite Information Page

Labradorite

6 - 6.5

Labradorite Information Page

Cassiterite

6 - 7

Cassiterite Information Page

Nephrite Jade

6 - 6.5

Nephrite Jade Information Page

Sunstone

6 - 6.5

Sunstone Information Page

Moonstone

6 - 6.5

Moonstone Information Page

Maw-Sit-Sit

6 - 7

Maw-sit-sit Information Page

Kyanite

6 - 7

Kyanite Information Page

Jadeite

6 - 6.5

Nephrite Information Page

Andesine Labradorite

6 - 6.5

Andesine Labradorite Information Page

Star Moonstone

6 - 6.5

Star Moonstone Information Page

Rainbow Moonstone

6 - 6.5

Rainbow Moonstone Information Page

Hackmanite

5.5 - 6

Hackmanite Information Page

Nuumite

5.5 - 6

Nuumite Information Page

Scapolite

5.5 - 6

Scapolite Information Page

Opal

5.5 - 6.5

Opal Information Page

Opal Doublet

5.5 - 6.5

Opal Doublet Information Page

Moldavite

5.5

Moldavite Information Page

Moss Opal

5.5 - 6.5

Moss Opal Information Page

Sodalite

5.5 - 6

Sodalite Information Page

Rhodonite

5.5 - 6.5

Rhodonite Information Page

Boulder Opal

5.5 - 6.5

Boulder Opal Information Page

Fire Opal

5.5 - 6.5

Fire Opal Information Page

Hematite

5.5 - 6.5

Hematite Information Page

Cat’s Eye Scapolite

5.5 - 6

Cat’s Eye Scapolite Information Page

Apatite

5

Apatite Information Page

Chrome Diopside

5 - 6

Diopside Information Page

Smithsonite

5

Smithsonite Information Page

Snowflake Obsidian

5 - 5.5

Snowflake Obsidian Information Page

Sphene

5 - 5.5

Sphene Information Page

Lapis Lazuli

5 - 6

Lapis Lazuli Information Page

Tremolite-Hexagonite

5 - 6

Tremolite-Hexagonite Information Page

Star Diopside

5 - 6

Star Diopside Information Page

Obsidian

5 - 5.5

Obsidian Information Page

Cat’s Eye Apatite

5

Cat’s Eye Apatite Information Page

Tashmarine Diopside

5 - 6

Tashmarine Diopside Information Page

Turquoise

5 - 6

Turquoise Information Page

Hemimorphite

5

Hemimorphite Information Page

Larimar

4.5 - 5

Larimar Information Page

Gaspeite

4.5 - 5

Gaspeite Information Page

Charoite

4.5 - 5

Charoite Information Page

Fluorite

4

Fluorite Information Page

Variscite

4 - 5

Variscite Information Page

Rhodochrosite

4

Rhodoschrosite Information Page

Ammolite

4

Ammolite Information Page

Malachite

3.5 - 4

Malachite Information Page

Azurite

3.5 - 4

Azurite Information Page

Sphalerite

3.5 - 4

Sphalerite Information Page

Calcite

3

Calcite Information Page

Coral

3 - 4

Coral Information Page

Verdite

3

Verdite Information Page

Pearl

2.5 - 4.5

Pearl Information Page

Lepidolite

2.5 - 3

Lepidolite Information Page

Chrysocolla

2 - 4

Chrysocolla Information Page

Amber

2 - 2.5

Amber Information Page

Seraphinite

2 - 4

Seraphinite Information Page

Pa