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Onyx

A species of Agate, Also known as Black Agate

Onyx is formed of alternating bands of chalcedony, just like agate; they differ only in the form of the bands, as agate shows curved lines while those in onyx are straight and parallel. Its name accordingly comes from the Greek word for "fingernail," as a brown stone with white bands can indeed resemble the shape of a fingernail.

Hardness:

6.5 - 7

Density:

2.55 - 2.7 g/cm³

General Info About Onyx

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Physical Properties of Onyx

Luster

Waxy, Vitreous

Diaphaneity

Translucent to opaque

Colors

Black, white

Magnetism

Non-magnetic

Tenacity

Brittle

Cleavage

None

Fracture

Conchoidal, Subconchoidal

Streak

White

Crystal System

Trigonal

Hardness

6.5 - 7 , Hard

Density

2.55 - 2.7 g/cm³, Normal Weight

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Chemical Properties of Onyx

Chemical Classification

Silicates

Formula

SiO₂

Elements listed

Si, O

Optical Properties of Onyx

Refractive Index

1.530-1.543

Birefringence

0.004

Pleochroism

None

Dispersion

0.013

Optical Character

Biaxial positive

Health Risk of Onyx

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What is the hazards of Onyx?

Harm Type

Physical Toxicity

Onyx in powdered form can be toxic due to its Crystalline Silica content.

Quartz, silica, crystalline silica and flint are non-toxic materials, but very fine dust containing quartz, known as respirable crystalline silicon (RCS), can cause serious and fatal lung disease. Lapidaries should exercise caution when cutting silica.

How to prevent the risks of Onyx?

Avoid long-term inhalation of its dust!

Onyx is typically non-toxic unless it's in powder form. Long-term exposure to finely ground powder may lead to silicosis. Therefore, when cutting or polishing onyx, be sure to wear a dust mask to avoid inhaling its dust.

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Rarity

Common

Characteristics of Onyx

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Rock Types of Onyx

Onyx is formed of bands of chalcedony in alternating colors. It is cryptocrystalline, consisting of fine intergrowths of the silica minerals quartz and moganite. Its bands are parallel to one another, as opposed to the more chaotic banding that often occurs in agates.

Sardonyx is a variant in which the colored bands are sard (shades of red) rather than black. Black onyx is perhaps the most famous variety, but is not as common as onyx with colored bands. Artificial treatments have been used since ancient times to produce both the black color in "black onyx" and the reds and yellows in sardonyx. Most "black onyx" on the market is artificially colored.

Cultural Significance of Onyx

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Uses of Onyx

Uses of onyx are ornamental, but various. In ancient history, it was used for hardstone carving and jewelry, most notably for cabochons or beads. Intaglio engraved gems made from onyx were also popular, and Ancient Egyptians used it for bowls and other pottery items. Today, it remains a popular gemstone, although many onyx stones on the market are made by dyeing other minerals.

The Meaning of Onyx

According to myth, onyx was formed from the fingernails of the Roman goddess Venus, after Cupid missed the target and clipped just her nails. The nails fell into the water and turned into stones. Historically, black onyx was associated with bad luck and sadness, while the red and white varieties were used to diminish the bad luck charms of the black onyx.

Distribution of Onyx

Onyx is a gemstone found in various regions of the world including Yemen, Uruguay, Argentina, Australia, Brazil, Canada, China, Czech Republic, Germany, Pakistan, India, Indonesia, Madagascar, Latin America, the UK, and various states in the US.

Etymology of Onyx

Onyx comes through Latin (of the same spelling), from the Greek ὄνυξ, meaning "claw" or "fingernail". Onyx with flesh-colored and white bands can sometimes resemble a fingernail. The English word "nail" is cognate with the Greek word.

Healing Properties of Onyx

Onyx is considered an emotional healing stone that is often used to aid the grieving process and alleviate stress. This stone is associated with strength and stamina as well as the building of self-confidence and self-control. Wear it as jewelry, use it for meditation, or carry it close to the body.

Chakras

Root

Onyx as a Zodiac Stone

Onyx is the stone for those who are born under the zodiac sign of Leo. It is a protective stone that shields its user from negative forces and restores a sense of courage. The perfect stone for the strong and brave Leo, it encourages discipline and stability to keep them focused and balanced.