Like agate, onyx is a type of chalcedony, which is a cryptocrystalline quartz. The key difference between the two stones is that the characteristic bands we admire in agates are curved, while those in onyx are straight, usually alternating between black and white or brown and white.

Onyx is a favorite material for cameo makers, who will frequently carve into, say, a white layer until they’ve removed enough of it to reveal the black layer below. In this case, the result is a white image that appears to float on an inky background. Onyx is also cut into beads for necklaces, teardrops or geometric shapes for earrings, and bold cabochons for rings.

Also like agate, onyx is easy to dye. The recipe calls for boiling the stone in a sugar solution, then letting it steep in sulphuric acid. When the acid hits the sugar, black carbon is created, which seeps into the stone. This technique is used a lot because the demand for black onyx far outstrips the supply. In fact, dyed black onyx was used liberally during the Art Deco era, when dramatic contrasts and hard edges were all the rage.


Best of the Web (“Hall of Fame”)

All About Jewels Dictionary

All About Jewels Dictionary

This incredible reference dictionary on jewelry, from Enchantedlearning.com, is both beautiful and comprehensive. S… [read review or visit site]

Morning Glory Antiques and Jewelry

Morning Glory Antiques and Jewelry

Jewelry collectors, feast your eyes on this internet gem! It's a goldmine of jewelry information featuring all styl… [read review or visit site]

Cathy Gordon's Jewelry Gallery

Cathy Gordon's Jewelry Gallery

With its vast galleries featuring clear images of jewelry and style, this site really covers it all! Divided up by … [read review or visit site]

Jewel History

Jewel History

Since March of 2007, readers of Lori Ettlinger Gross’s Jewel History blog have been treated to her weekly (someti… [read review or visit site]



Clubs & Associations

Other Great Reference Sites

Most watched eBay auctions    

Fine Antique Victorian 14k Gold Onyx Pearl Diamond Flower Locket BroochBvlgari-bvlgari Onyx 18k Yellow Gold Bracelet 25.0 Grams NrGeorgian 9ct Gold Eye Portrait Miniature Onyx Brooch .. C1800Estate Jade Black Onyx 14k Yellow Gold Bracelet Bangle 21.3 Grams NrEstate Diamond Ruby Emerald Onyx 18k Gold Elephant Charm Bracelet 21.4 Grams NrMaz Mabe Pearl 7.00ct Tourmaline Onyx 14k Gold Large Earrings 42.3 Grams NrCorletto 18k Gold Adorable Pink Sapphire/onyx Kitty Cat Pin/broochJudith Ripka Sterling Silver Black Onyx Double Strand NecklaceEstate Black Onyx Pearl 9k Yellow Gold Earrings NrFine 9ct / 9k 375 Gold Swivel Bloodstone Onyx And Cornelian Watch FobAntique Circa 1920 Handmade Mexican Cats Black Onyx & Enamel Pin, NrLrg Antique Early 20thc Victorian Sterling Silver Black Onyx Stone Butterfly PinFannie Platero Navajo Sterling Silver Turquoise Shell Onyx Inlay Cuff Bracelet JMens 1940s Vintage 10k White Gold 0.03 Ct Brilliant Cut Diamond Black Onyx RingNavajo Hallmarked "ek" Sterling Silver Turquoise Onyx Shell Inlay Earrings J MOld Pawn Vintage Navajo Row Bold Black Onyx Sterling Bracelet Judith Ripka Sterling Silver Cz & Black Onyx EarringsEstate Jade Onyx 14k Yellow Gold Link Bracelet 9.1 Grams NrEstate Diamond Garnet Onyx 14k White Gold Band Ring Nr14k Solid Gold Vintage Asian-style Dragon Necklace Pendant 4.5 Grams**estate 14k Yellow Gold Large Onyx Ring 19x16.7mm Size 5.25 5.1 Grams Long Big Vintage Navajo Stamped Sterling Silver Dangle Onyx Earrings WesternVintage Sterling Silver - Navajo Black Onyx Flower Cuff 16.2g - Bracelet (5.5")Fine Vintage 14k Solid Gold Art Deco Onyx Ring Sz 5 1/2Art Deco 14kt Yellow Gold & Black Onyx, 1926 Ladies Class Ring Size 5 1/2 ~nr~Navajo Hallmarked "ek" Sterling Silver Turquoise & Onyx Inlay Earrings J MWonderful Estate 10k Yellow Gold Black Onyx & European Cut Diamond Ring Mens Estate $4700 14k Yellow Gold 6.00 Ct Natural Black Onyx And Diamond RingAntique Vintage C. 1950 Deco Mid Century 14k Gold 1.26 Ct Diamond Onyx Earrings!Silver Opal Unicorn Pendant OnyxLarge Heavy, & Rare Tiffany & Co Solid 18k Gold & Black Onyx Man's Estate RingVintage 1970s Georg Jensen Silver & Black Onyx Ring Size MVintage Tabra Black Onyx Pierced EarringsVintage Sterling Silver - Antique Mexico Green Onyx 44.5g - Bracelet (7") Ya3172Sterling Silver, Black Onyx & Marcasite Judith Jack Hinged Bangle Bracelet Vintage Sterling Silver - Antique Taxco Black Onyx 54.2g - Bracelet (7") Ya3242Vintage Native American Sterling Silver Earrings W/ Onyx Stone Inlay 4 PairRare Vintage Mickey Mouse Zuni Sterling Silver Turquoise Onyx Mop Coral RingVictorian Hallmarked Arco Sterling Silver Ornate Marcasite Filigree Onyx PendantStunning *large* Vintage Mexican Green Onyx Mayan Design Alpaca Bracelet C.1950s4.9g 10k Solid Gold Art Deco Onyx And Diamond Ring Sz 9Vtg Navajo Indian Large Black Onyx Stone Sterling Silver Pendant Necklace 14 1/4Antique Victorian Silver 12.0cts Siberian Amethyst Onyx Scorpion Brooch 18901993 Hallmarked Solid Sterling Silver & Onyx Taxco Statement Bangle BraceletBeautiful Unique Vintage Native American Navajo, J. Woolsey, Sterling/onyx BraceKarl Lagerfeld Vintage Long Gold Earrings W Black Onyx Oval Drop Vintage Sterling Silver - Zuni Turquoise Onyx & Opal 8g - Ring (7.5) Mens Wm5212Pre-1948 Mexico Sterling Silver Black Onyx Art Deco 17.5 Inch Necklace 102 Grms Vintage Huge Massive Onyx Old Pawn Navajo Sterling Silver Bracelet Victorian 15ct Solid Gold Onyx Seed Pearl Lozenge Shaped Mourning Brooch C1870Really Nice Vintage Men's B&f Ring 14k Gold W/black Onyx & Diamond - Size 9 !!Vintage Sterling Silver - Taxco Mexico Green Onyx Mask 80g - Bracelet (7.25")Vintage Sterling Silver - Navajo Signed Onyx Flower Cuff 41g - Bracelet (6.5")Vintage Sterling Silver - Black Onyx Garnet & Marcasite 15g - Brooch Xt7842Navajo Hallmarked "ek" Sterling Silver Turquoise Onyx Shell Inlay Earrings J M~vtg~mexican~sterling Silver~carved~black Onyx~aztec Mask~ornate~dangle~earringsDeco 1920's Natural 4ct Emerald Cut Amethyst Mens 10k Yellow Gold Ring Sz 9Vintage Sterling Silver - Navajo Black Onyx 5.5g - Pendant Xt3572Stylish Vintage Sterling Silver Designer Celtic Black Onyx Ring Size N1/2Vintage Onyx Smooth Sterling Silver 925 J Hook Earrings (4.3g)