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    

Antique C. 1940 Art Deco 14k White Gold Diamond Onyx Filigree Lavaliere Pendant!Antique C 1920 Deco 14k Yellow Gold Seed Pearl Green Onyx 1.25" Dangle Earrings!Vintage Tiffany & Co Angela Cummings 18kt Diamond Emerald Onyx Necklace EarringsAntique 1950 Deco 14k Gold Green Black Onyx Intaglio Cameo Tagliamonte Earrings!Finest Vintage 9ct Gold Blue Agate/onyx Pear Shaped Watch Fob/pendantAntique 1950 Deco 14k Gold Multi Color Onyx Intaglio Cameo Tagliamonte Necklace!Resale Dealer Lot Of 14 Authentic Silpada Sterling Silver Rings Pearl Onyx CzArt Deco Era 14k White Gold Black Onyx Filigree Ring - Sz 5 1/2 - 3.5 Gms Norsv!Vintage Old Pawn Silver Mans Ring Set W/ Lapis & Onyx Size 10+ SignedVintage Taxco Bangle Bracelet Cuff Turquoise, Lapis Onyx 29g Sterling SilverVan Cleef & Arpels Alhambra Necklas And Earing Set 18-karat Yellow Gold And OnyxVintage Rhinestone Sterling Silver Rivoli Cameo Onyx Perfume Poison 54 Ring LotHsn Sold Out Rare Vintage Heidi Daus "impressionism" Onyx NecklaceVintage Solid Silver Onyx Norman Grant Scottish Hallmarked Pin BroochVintage Wide Signed Zuni Sterling Silver Mosaic Inlay Turquoise Onyx BraceletVintage Sterling Silver Spiny Oyster Onyx Southwestern Gemstone Jewelry EarringsVtg Black Onyx Turquoise Purple Amethyst Heavy Cast Sterling Silver Ring Lot 7Rare Antonio Pineda Four Tier Silver And Onyx EarringsVintage Lot Brooch Pin Cameo Carved Shell Onyx Abalone Woman Resin Tiered! F341Vintage Hecho En Mexico Sterling Silver Onyx Necklace 3.6 Oz1940s Vintage 10k Yellow Gold Single Cut Diamond And Black Onyx RingVintage Solid Sterling Silver Large Onyx Signet Ring - Size N - 8.3g!Vtg Sterling Silver 925 Ring Lot Sizes 4.5-7.5 Turquoise Western Onyx F220Vintage Southwest Handcrafted Amethyst Onyx Marcasite Sterling Silver EarringsDavid Yurman Black Diamond Sterling Silver Exotic Onyx Cable Dog Tag NecklaceVintage~navajo~sterling Silver~turquoise~howlite~coral~onyx~inlay~ringVintage Black Onyx Sterling Silver Mexico Mexican BraceletVintage Camphor Glass Amethyst Onyx Sterling Silver Filigree RingVintage 950 Sterling Silver & Onyx Necklace, Taxco Mexico Fabaro Tf-86, 46.7gVintage Mexico Onyx Triangle Sterling Silver 925 Post Earrings (19.2g)Vintage Onyx Cut Out Sterling Silver 925 Bracelet (10.4g) 7.0in1969 Vintage 9ct Solid Gold & Black Onyx Gents Signet Ring Uk T 1/2 Us 10 - 2.7gVintage 14k Gold Ring With Diamond And OnyxOld Pawn Vintage Navajo Kingman Black Onyx Old Clip On EarringsVintage Sterling Native American Navajo Onyx Ring 1-5/8" Size 6 (6gm)Vintage Hz 14k Yellow Gold Dangle Onyx Heart Lariat Chain NecklaceOld Vintage 14k Gold Black Sapphire Or Onyx RingDavid Webb Vintage 18k Yellow Gold Onyx & Diamond 1.5 Carat EarringsOrnate Vintage Mexico Sterling Silver Wide Onyx Cuff Bracelet SouthwesternVintage Onyx Beaded Scroll Rectangle Sterling Silver 925 J Hook Earrings (4.4g)10k Gold Mens Oval Black Onyx Ring Size 10 Estate JewelryVintage 14k Yellow Gold 12x9mm Oval Black Onyx Ring Size 6.5 Not ScrapMazza Designer Earrings Doorknocker Sterling Silver 14k Yellow Gold Pearl OnyxVintage Fancy Gold Fob / Pendant Large Swivel Black Onyx Bloodstone Cornelian Vintage Zuni Knifewing Man Pin ~ Turquoise, Coral, Abalone, Onyx12k Gold & Sterling Silver Vintage 925 Eagle Signet Onyx Ring Sz 10 (8.6g-488943Vintage Sterling Silver 925 Marcasite Black Onyx Bracelet 7"Vintage Scottish Celtic Lapis,jade,black Onyx,turquoise,carnelian BraceletAmazing Vintage Hallmarked 9ct Yellow Gold Carnelian & Onyx Swivel FobVintage Jewellery Delightful Suarti Silver & Onyx Pendant Drop EarringsAntique Victorian Onyx Square Mourning10kt Gold Filled Ring Gorgeous! Size 10 Amy Kahn Russell Vintage Carved Rabbit On Oval Onyx Brooch PinFinest Antique Victorian Black Onyx Rose Gold Seed Pearl Brooch Vtg Mexican Silver Carved Green Onyx Ornate Pendant Necklace6o Grams! Turkish Topaz Onyx 925k Sterling Silver NecklaceSale Vintage Mexican 925 Sterling Silver Onyx Jewelry Necklace Earrings Bracelet.925 Sterling Silver Vintage Green Malachite Black Onyx Bangle Bracelet (35.2g)Pretty Vintage Silver Cloud Sterling Silver Amethyst & Onyx Ring - Size 7Vintage Onyx Or Enamel Fancy Scroll St`erling Silver 925 Cuff Bracelet (52.2g)Judith Ripka Sterling Silver Black Onyx Bead Dangle Pierced Earrings