Bull's eye: meaning, heat treatment and care

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Bull's eye is a heated tiger's eye that takes on a deep red-brown. It is an old, common treatment that is worth knowing about.

Key points

Colour	Red-brown to dark red, with a more subdued silky sheen
Mineral family	Fibrous quartz (silica), the same material as tiger's eye
Mohs hardness	7
How it is obtained	Heating of a brown tiger's eye; the colour turns reddish
Other names	Ox eye, bull's eye (œil de bœuf, œil de taureau in French)
Original deposits	Mainly South Africa (as for tiger's eye)
Traditional association	Root chakra, vitality, grounding
Care	Lukewarm water, soft cloth; avoid intense heat and prolonged sunlight

What is bull's eye?

Bull's eye, more often called ox eye (œil de bœuf), is not a distinct stone: it is tiger's eye that has been heated. When a brown tiger's eye is brought to a high, controlled temperature, the iron it contains oxidises further and the stone takes on a deep red-brown, with a silky sheen that is more muted than that of the golden version.

The material is therefore the same: a fibrous quartz whose amphibole fibres have been replaced by silica, with a hardness of 7. The original deposits are found mainly in South Africa. Older works refer to it as “ox eye” or “bull's eye” (œil de taureau in French), the word “eye” referring to the moving reflection, as in tiger's eye.

Note: the name “bull's eye” is sometimes applied to unrelated objects (round windows, a heraldic motif); in the world of stones, it refers to this heated fibrous quartz.

Traditional symbolism

Red-brown evokes soil, blood, strength and perseverance. In contemporary tradition, bull's eye is more grounded and more “earthly” than tiger's eye, whose colour is more solar. It is associated with vitality, endurance and the courage to keep going.

These readings are symbolic and recent: there is no ancient text devoted specifically to this stone. Take it for what it is, a warm and beautiful material, and give it the meaning you wish.

Traditional correspondences

Area	Association cited	Note
Chakra	Root	Often cited for red-brown stones; see the root chakra
Element	Earth, fire	Depending on the authors
Sign	Taurus, Aries, Capricorn	The name naturally evokes Taurus; see Taurus

How to use it

As a bracelet or necklace: warm beads that go well with leather, wood and earthy tones.
As a cabochon ring: the colour stands out well in a domed cabochon.
Displayed: an egg or a tumbled stone near the front door is a decorative gesture, sometimes linked to the idea of “taking root” in the place.
In meditation: feel the weight and coolness of the stone in your hand, then take three slow breaths.

For grounding, it pairs well with lava stone or red jasper.

Care and cleansing

Like tiger's eye, from which it comes, bull's eye is robust: hardness 7, good tolerance of lukewarm water. Clean it with a soft cloth and a little soap, then dry it.

The stone has already been heated, but avoid exposing it to further heat (oven, radiator, hair dryer): the colour can still shift.
Avoid salt and acids.
Avoid prolonged sun, which can lighten the colour.
Avoid hard knocks along the fibres.

Gentle smoke, moonlight or selenite: see our guide.

Recognising bull's eye and avoiding surprises

Bull's eye is by definition a treated material (heated). This is not a defect, but it must be disclosed. Here is what to distinguish:

Established, declared heating: deep, uniform red-brown with the silky sheen preserved. This is the normal case.
Dyeing: a very saturated bright red or orange, with concentrations of colour in the cracks, points rather to a dyed quartz.
Other red-brown stones: red jasper or iron eye (a mix of jasper, haematite and tiger's eye) look more matte or more banded, without a clear sheen.
Glass “cat's eye”: a very sharp, regular reflection on a light piece is suspect.

How to choose

Look for a warm, uniform tone, a reflection visible when you tilt the stone, and an even polish. In beads, the uniformity of a bracelet is a good sign. A colour that is too bright should be compared with natural samples.

The price remains modest, close to that of tiger's eye. A tumbled stone is enough to discover the material; a cabochon or a bracelet suits daily wear. See also the stone glossary for the terms “treated” and “dyed”.