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Carnelian

Orange chalcedony, the signet stone of Egypt and Rome.

Family
Chalcedony
Formula
SiO₂
Mohs
6.5 to 7
System
Trigonal

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Science

Carnelian is translucent chalcedony coloured by iron oxide. Indian material is traditionally left in the sun for weeks to deepen the orange to red. The boundary with sard, the browner variety, is a matter of taste rather than chemistry.

Mineral
Chalcedony (variety)
Formula
SiO₂
Crystal system
Trigonal
Mohs hardness
6.5 to 7
Specific gravity
2.58 to 2.64
Refractive index
1.530 to 1.540
Lustre
Waxy to vitreous
Colours
Orange, Red-orange, Brown

Composition

SiO₂. Made of Silicon, Oxygen, with trace Iron responsible for colour.

in formula trace, gives colour

Origin

  • India
    Gujarat, sun-darkened
  • Brazil
  • Uruguay
  • Madagascar
  • Egypt
    Eastern Desert, historic

Filled dots are primary sources

Rarity

Abundant
1 of 5

Common. Much orange chalcedony sold as carnelian is heated or dyed agate.

  1. 1 Abundant
  2. 2 Common
  3. 3 Uncommon
  4. 4 Rare
  5. 5 Exceptional

Hardness

Carnelian sits at 6.5 to 7 on the Mohs scale. It will scratch glass and holds a polish in daily wear.

Fingernail
Copper coin
Knife, glass
Steel file
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Energy

Associations from crystal-healing tradition, recorded here as folklore. They are not medical claims.

Chakras

  • Sacral
  • Root

Element

  • Fire

Zodiac

  • Aries
  • Leo
  • Virgo

Planets

  • Mars
  • Sun

Properties

  • Vitality
  • Courage
  • Creativity
  • Motivation
  • Warmth

Lore

Egyptians called it the 'setting sun' and carved it into amulets for the dead; Tutankhamun's jewellery is full of it. Hot wax does not stick to carnelian, which made it the favoured stone for Roman signet rings.

The Prophet Muhammad is recorded as wearing a carnelian seal, and the stone remains common in Islamic rings today.

  • Sard
    The same stone in a darker, browner shade.
  • Seal
    Wax releases cleanly from carnelian, hence its use in signets.