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 JewelHistory blog have been treated to her weekly (sometim… [read review or visit site]



Clubs & Associations

Other Great Reference Sites

Most watched eBay auctions    

Estate Black /blue 4.50ct Opal Onyx 14k Gold Oval Large Cufflinks 18.4 Grams NrVtg Kenneth Jay Lane Kjl Art Deco Revival Faux Coral Onyx Rhinestone NecklaceTiffany & Co Black Onyx Sterling Silver Bead Long Strand Necklace 75.6 Grams NrAntique Victorian Edwardian 14k Gold Onyx & Seed Pearl Mourning Locket NecklaceAaron Toadlena Navajo Vintage Sterling Silver Coral Onyx Inlay Bib Necklace 36gEstate Big Onyx 14k Gold Large Ring 30.7 Grams NrDan Frere Sapphire Ruby Onyx 14k Gold Dog Pin 6.0 Grams NrBarbara Bixby 18kt Yellow Gold Sterling Flourite Pink Brazilian Garnet Onyx RingAntique $1,900 10k Yellow Gold Oval Cut Black Onyx Diamond Mourning Ring 3.3gAntique Mourning Locket Pendant-black Onyx/obsidian-12k Gold-seed PearlsVtg Heavy 93 Grams Sterling Silver Black Onyx Necklace Mexico MexicanEstate Onyx Pearl Two Toned 9k Gold Square Pendant NrOnyx Opal Jade Ruby Coral 14k Gold Chinese Dragon Large Pendant 14.9 Grams NrVtg Gilbert Nelson Navajo Opal Black Onyx Sterling Silver Pendant Flush InlayVictorian Romantic Revival Style 14k Gold Onyx & Seed Pearl Ring Size 5 Btg NrStunning Art Deco 925 Silver Marcasite Onyx / Jet Mother Of Pearl RingEstate Topaz Aquamarine Onyx 18k Gold Silver Bracelet 39.8 Grams NrEstate 1.00ct Ruby Onyx 9k Gold Cameo Enamel Ring 7.3 Grams NrVintage Malachite Onyx & 14k Gold Bead 38" Necklace Vintage 14k Solid Yellow Gold Ladies Cocktail Ring Polished Onyx Oval GemstoneEstate Onyx Diamond 14k White Gold Small Pendant NrFine Heavy Art Deco Design Large Onyx 14ct Gold Ring.Mens Roaring 1920s Art Deco Gatsby Era Onyx 10k Intaglio Soldier Cameo Ring 10.5Big Chic Vintage Modernist Sterling Silver Onyx Pendant NecklaceVictorian 10k Rose Gold Onyx Carnelian Banded Agate Stone Photo Locket PendantEstate Antique 14k Solid Gold Black Onyx Seed Pearl Mourning Earrings-scrap? Nr!Wonderful Wide Vintage Mexico Sterling Silver & Onyx Cuff Bracelet │ G AtGorgeous Vintage Southwestern Sterling Silver & Black Onyx Fleur De Lis RingAntique Victorian Mourning Gf Onyx Cameo Carnelian Hidden Picture Locket FobGorgeous Wide! Vtg Mexican Mexico Carved Onyx Sterling Bracelet!! Sm58710k Solid Gold Mens Heavy Antique Black Onyx & Tiger's Eye Ring Sz 10.75 Best!Vintage 8mm Onyx & 14k Gold Bead 30" Necklace Vintage Mens 10k Yellow Gold Black Onyx Signet Letter Initial N Ring 9.5 SignedPre-1948 M. Ocampo Mexico Sterling Silver Abalone & Onyx Art Deco Necklace TaxcoAntique Art Deco 14k W Gold Filigree Onyx Diamond Ring ObOld Pawn Vintage Ss Dyed Onyx Necklace / Choker Navajo Signed E. Yazzie 56gVtg Mexico Sterling Silver & Black Onyx Large Link Taxco Necklace 80 GramsVintage Taxco Sterling Silver Bracelet Malachite Onyx Blue Gem Stone Tribal 115gVintage Onyx Mop Cameo Pendant W/ 14 K Filigree Yellow Gold Frame & Pearl ** EVintage Sterling Korean War Veteran Us Army Signet Onyx Class Ring Sz 12 25gramsAntique 18k White Gold, Onyx, Diamond Ring Size 7Fine Art Deco Design Onyx Gold Signet RingVintage Signed Navajo Silver Turquoise Onyx Sugilite Malachite Choker NecklaceVtg Zuni Indian Coral Onyx Turquoise Mop Inlaid Sterling Silver Cuff BraceletHeavy Vintage 17" Onyx Bead Necklace 14k Gold Pendant With Ancient Coin - 50 GrmFine Blood Stone,carnelian & Onyx Spinning Gold Fob PendantVintage Taxco Mexico Sterling Silver Big Ornate Onyx Pendant Statement Necklace(5) Vintage Sterling Silver Earrings, Marcasite, Amethyst, Cameo, OnyxNice Vintage Onyx Pearl 14k Gold Platinum Cuff Links Collar Studs Art Deco White Gilson Opal Onyx Set Pendant Earrings 925 Sterling SilverVintage Art Deco Sterling Silver Onyx Marcasite Women's Dangle Pierced EarringsVintage 14k Gold, Onyx And Inlaid Opal Butterfly Pendant 2.3 GramsVintage Antonio Pineda Sterling 970 Black Onyx Chunky Cufflinks Estate Antique Art Deco Solid 10k Natural Diamond Onyx Enamel Eastern Star RingModern Crystal White Onyx Sterling Silver Ring 20.9 Grams NrAntonio Pineda Sterling Silver Cufflinks 970 Taxco Green Onyx ModernistVintage 9 Ct Gold Black Onyx Ring Hallmarked 7.8 Grams Size VBeautiful Vintage 14k Yellow Gold Black Onyx Bead Necklace&braceletPre-1948 M. Ocampo Mexico Sterling Silver Abalone & Onyx Art Deco Bracelet TaxcoVintage Opal & Onyx Sterling 10k Pirate Ships & Dolphins Man' Ring