search
  • Sign In
    Sign Up
  • English speaking customer support only

    1-800-464-1640

  • Change Language
  • USD
By Gavin Clarke Reviewed By Andreas Zabczyk Feb 04, 2010 Updated Jan 23, 2019

Red Cinnabar Gemstones


The distinction between a mineral and a gemstone is not always well-defined. In general we can say that an attractive mineral will find use as a gemstone only if it is sufficiently hard and durable to be set in jewelry.

Cinnabar Crystals from Spain
Cinnabar Crystals from Spain

Having said that, there are a number of interesting minerals that are quite soft but attract gemstone collectors nonetheless. A good example is cinnabar. It is not only a colorful mineral, but it also has some quite unusual gemological properties.

Cinnabar is composed of mercury sulphide and is the common ore of mercury. Its typical color is brick-red, cinnamon red or bright scarlet. Generally cinnabar occurs as a vein-filling mineral associated with recent volcanic activity or alkaline hot springs. Cinnabar was known to the ancient Romans both as a pigment and a source of mercury. It was also used for decorative purposes in South America and China.

Cinnabar is notably soft, with a hardness of only 2 to 2.5 on the Mohs scale. However, it is remarkably dense, with a specific gravity of 8.1. By way of comparison, the most dense gemstones commonly sold are spessartite garnet (which has a specific gravity of 4.12 to 4.18), zircon (3.93 to 4.73), sapphire (3.95 to 4.03) and ruby (3.97 to 4.05). Hematite, a less common gemstone, has a density of 5.12 to 5.28.

Indeed, there are only a few minerals of any sort that are denser than cinnabar. These minerals tend to be metals, such as gold (with a density of 15.5 to 19.3) and silver (9.6 to 12.0). For a non-metallic mineral, cinnabar is unusually heavy.

Cinnabar Ore
Cinnabar Ore

Cinnabar is not only remarkably dense, it also has an extremely high refractive index (2.905 to 3.256), much higher than that of diamond (2.417 to 2.419), zircon (1.810 to 2.024), demantoid garnet (1.88 to 1.94) or sapphire (1.762 to 1.778). Given these unique properties it is not surprising that cinnabar is popular with collectors.

Cinnabar forms as trigonal crystals, but large, individual well-formed crystals are rare. Usually cinnabar is found in crusts or crystal complexes and massive forms are common. Some rare, fine crystals have been found in Spain and China.

Notable occurrences of cinnabar are in Spain (Almaden), Slovenia (Idrija), China (Hunan Province) the USA (California, Oregon, Texas and Arkansas).

STAY IN TOUCH
*You're signing up to receive GemSelect promotional email.
Partners and Trust Payment options

Switch to Mobile Version

Privacy Notice © 2005-2023 GemSelect.com all rights reserved.

Reproduction (text or graphics) without the express written consent of GemSelect.com (SETT Company Ltd.) is strictly prohibited.

1174

More Shapes
Popular Gemstones
  • Sapphire
  • Emerald
  • Ruby
  • Aquamarine
  • Zircon
  • Opal
  • Topaz
  • Tourmaline
  • Garnet
  • Amethyst
  • Citrine
  • Tanzanite
All Gemstones (145)
A B C D E F G H I J K L M N O P Q R S T V Z
  • Actinolite Cat's Eye
  • Agate
  • Agate Geode
  • Almandine Garnet
  • Amazonite
  • Amethyst
  • Amethyst Geode Slice
  • Ametrine
  • Ammolite
  • Andalusite
  • Andesine Labradorite
  • Apatite
  • Aquamarine
  • Aventurine
  • Azotic Topaz
  • Azurite
  • Black Opal
  • Bloodstone
  • Boulder Opal
  • Carnelian
  • Cat's Eye Apatite
  • Cat's Eye Aquamarine
  • Cat's Eye Gemstones
  • Cat's Eye Moonstone
  • Cat's Eye Opal
  • Cat's Eye Scapolite
  • Chalcedony
  • Charoite
  • Chocolate Opal
  • Chrome Diopside
  • Chrysoberyl
  • Chrysoberyl Cat's Eye
  • Chrysocolla
  • Chrysoprase
  • Citrine
  • Color Change Gemstones
  • Color-Change Diaspore
  • Color-Change Fluorite
  • Color-Change Garnet
  • Coral
  • Demantoid Garnet
  • Dendritic Agate
  • Diamond
  • Druzy Amethyst
  • Druzy Azurite
  • Druzy Citrine
  • Druzy Variscite
  • Emerald
  • Enstatite
  • Fire Agate
  • Fire Opal
  • Fluorite
  • Fossil Coral
  • Garnet
  • Golden Beryl
  • Grandidierite
  • Grossularite Garnet
  • Hawk's Eye
  • Hematite
  • Hemimorphite
  • Hemimorphite Druzy
  • Hessonite Garnet
  • Howlite
  • Idocrase
  • Imperial Topaz
  • Iolite
  • Jade Gemstones
  • Jadeite
  • Jasper
  • Kornerupine
  • Kunzite
  • Kyanite
  • Labradorite
  • Lapis Lazuli
  • Larimar
  • Malachite
  • Malaya Garnet
  • Mali Garnet
  • Maw-Sit-Sit
  • Moonstone
  • Morganite
  • Mother Of Pearl
  • Mystic Quartz
  • Mystic Topaz
  • Nuummite
  • Obsidian
  • Onyx
  • Opal
  • Opal Doublet
  • Opal In Matrix
  • Pearl
  • Peridot
  • Pietersite
  • Prehnite
  • Pyrite
  • Pyrope Garnet
  • Quartz
  • Quartz Cat's Eye
  • Quartz With Hedenbergite
  • Quartz With Marcasite
  • Rainbow Moonstone
  • Rainbow Pyrite
  • Rhodochrosite
  • Rhodolite Garnet
  • Rhodonite
  • Rose Quartz
  • Rubellite Tourmaline
  • Ruby
  • Ruby In Fuchsite
  • Ruby-Zoisite
  • Rutile Quartz
  • Sapphire
  • Scapolite
  • Scolecite
  • Seraphinite
  • Serpentine
  • Sillimanite
  • Sillimanite Cat's Eye
  • Smithsonite
  • Smoky Quartz
  • Snowflake Obsidian
  • Sodalite
  • Spectrolite
  • Spessartite Garnet
  • Sphalerite
  • Sphene
  • Spinel
  • Star Diopside
  • Star Garnet
  • Star Gemstones
  • Star Moonstone
  • Star Rose Quartz
  • Star Ruby
  • Star Sapphire
  • Strawberry Quartz
  • Sunstone
  • Tanzanite
  • Tiger's Eye
  • Tiger's Eye Matrix
  • Topaz
  • Tourmaline
  • Tsavorite Garnet
  • Turquoise
  • Variscite
  • Zircon
Main Categories
  • New Arrivals
  • Gemstone Lots
  • Calibrated Gemstones
  • Gemstones By Piece
  • Top Grade Gems
  • Matching Pairs
  • Cabochon Gemstones
  • Drilled Gems, Briolettes and Beads
  • Birthstones
  • Gemstone Carvings
  • Fancy Gemstones
  • Star Gemstones
  • Unheated Sapphire
English speaking customer support only

Toll Free - USA & Canada only:
1-800-464-1640

International:
+66-39609697

Save Money
No shipping Fees for Additional Items!
$8.90 Worldwide Shipping

Update Translation
 
Current Value
New Value
GemSelect Gemstones
X Close Window
Colored Gemstones
X Close Window
Colored Gemstones
X Close Window
Colored Gemstones
Size and Weight

Gems are always measured in Millimeter (mm)

Dimensions are given as;
length x width x depth,
except for round stones which are;
diameter x depth

Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

Size Comparison Chart