Most famous as a wonderfully shiny black gemstone, onyx also comes in a number of other colours (excluding blue and purple) that can feature fascinating alternating stripes.

The following guide will explore some interesting facts about these alluring gems, as well as outline some top buyers tips when it comes to shopping for an onyx necklace.

Jewellery Buyers Guide To Onyx Necklaces

Introduction to Onyx

This lustrous mineral is a banded variety of the chalcedony family – onyx forms in the gas cavities of lava and in addition to quartz it also contains fine intergrowths of morganite. It is a multi-layered gemstone, often featuring ribbons of colour which run parallel to each other instead of the more chaotic banding found in gems such as agate. Depending on these neat layers, onyx can be divided into distinct categories:

  • Onyx – distinguished by a black base with a white upper layer.
  • Cornelian onyx – has a red base.
  • Sardonyx – has coloured bands that are red instead of black.

Pure black onyx is without a doubt the most prized variety, since it captures and reflects light beautifully, particularly when cut into facets. It is not as common as the onyx variety that featured coloured bands. As with many other types of gems, since early times onyx and sardonyx have been artificially treated to enhance the shine and depth of their colour.

Main Sources of Onyx

While this gorgeous gem is found at many locations worldwide, mines in Brazil produce the highest gem quality onyx for use in jewellery. Other notable deposits include India, Hawaii, Madagascar, Pakistan, Uruguay and Sri Lanka.

Jewellery Buyers Guide To Onyx Necklaces

Buying Tips for Onyx Earrings

  • Onyx measures 7 out of 10 on the Mohs Scale of Hardness, meaning it is a relatively robust gem that will withstand accidental knocks and bumps when worn in jewellery reasonably well.
  • As mentioned, most onyx that is found on the marketplace has been artificially heat treated to improve its lustre – this does not reduce its value however.
  • Since the Roman times, artificial onyx has been produced from common chalcedony and plain agates (a cheaper gem), so do buy from a reputable retailer so that your pay for what you’re getting. A good way to you tell the difference however is to look at the banding structure – true onyx features parallel stripes, while stones like agate have a more uneven, chaotic structure.
  • Quality onyx has a highly reflective, well-polished surface, along with being a little transparent. The stone must also not have inclusions (minute inner cracks) that can be seen with the naked eye.
  • When shopping for a necklace, there are three main types which are classified by their length i.e. Choker necklaces are about 16 inches and sit on the collarbone, Princess necklaces are the most common and hang over the collarbone at 18 inches, while Opera length necklaces are 24 inches and are designed to dangle over a shirt or dress.
  • As with style, the necklace length you opt for is a personal choice, but it’s fashionable and a good idea to own a range of lengths so that you can mix and match of layer them depending on the outfit.
  • A tip in choosing the metal setting for a necklaces as well as any other type of jewellery is that yellow gold enhances warm complexions while platinum or white gold complements cooler skin tones.

Zodiac & Health Benefits of Onyx

Onyx is assigned to the astrological signs of Capricorn and Leo. In terms of health and healing properties, this captivating gem is thought to be highly effective in treating troublesome skin ailments, including infected wounds, inflammation, fungal infections and even sunburn. It is also thought that onyx aids in easing childbirth, calming amorous emotions and treating disorders of the feet and problems related to bone marrow.


Ranging from the varieties that feature fascinating parallel bands of colour to those that stand out for their famously shiny, pure black lustre, these gemstones are a must to add sophistication and a fashionably edgy style to any outfit. An onyx necklace is a particularly good choice, since it will catch the light beautifully as you move.

Comments to: Jewellery Buyers Guide To Onyx Necklaces

Your email address will not be published. Required fields are marked *