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    

Vintage Diamond 1.02ct Tourmaline Onyx Platinum Ring NrAntique Victorian 18k Gold Coral & Onyx EarringsGeorg Jensen Green Onyx Sterling Silver Pin 19.8 Grams Nr14k Yellow Gold Natural Inlaid Opal, Lapis & Black Onyx Curved Band Ring 4.2gVintage 1920's Art Deco Elegant Crystal & Onyx Glass Rhodium NecklaceVintage 1920s Art Deco 14k White Gold, Black Onyx & Omc Diamond, Filigree RingVintage Green Onyx 14k Yellow Gold Ring NrLot Of 1 Apple Green Jade, 1 Spinach Jade, 1 Onyx, 1 Agate Bangle Bracelets 4pcsModern Designer 18k Yellow Gold Black Onyx 1.04 Ct Diamond Elegant Earrings!1940's Vintage 10k White Gold European Cut Diamond And Black Onyx RingVintage Signed Ac Necklace Taxco Black Onyx Sterling Silver Mexico MexicanVintage 1920's Art Deco "german" Signed Black Onyx Marcasite Sterling NecklaceSterling 925 Vintage Mesh Bangle Bracelet Cuff Onyx Gemstone High Quality 5143Antique C. 1920 Deco Chinese 14k Gold Onyx & Chrysoprase Link Ladies Bracelet! Antique Sterling Silver Concho Belt, Necklace, Navajo Signed 68 G, 39" Old PawnAntique Diamond Black Onyx 14k White Gold Filigree Ring NrVintage Ford Sterling Silver Black Onyx 30 Year Size 11 Mens Heavy RingVtg 1970's .925 Sterling Silver & Black Onyx Slave Bracelet Ring Size 6 SignedLot Of 5 .925 Sterling Silver Mix Of Onyx Gemstone Cross Pendants #p3072Vintage 925 Sterling Silver Antique Finish Black Onyx Men Ring Sz 9.5 - 6gGorgeous Antique Vintage Mexican Taxco Sterling Black Onyx Panel 16" NecklaceFine Rose Gold Victorian Intaglio Ring Carved Onyx Estate Pc.Mourning Brooch W/ Onyx & Gold Fabulous All Original Condition, Pendent Nice!!Vintage Sterling Silver Heavy Black Onyx Bracelet 6.5'' (49.6g) - 415999Georg Jensen Denmark Antique 925 Sterling Silver Onyx RingOutstanding, Vintage Solid 9ct Gold & Diamond Agate / Onyx Set Fob * Beautiful *Designer Wh King 14k Yg Natural Black Oriental Onyx Scribe Clasp Bracelet 9.4gSterling 925 Vintage Ring Lot Sz 5-7 Onyx Lapis Turquoise Gems Butterfly 5148Vtg Old Pawn Sterling Silver Navajo Zuni Turquoise Onyx Inlay Cuff BraceletVintage Mikimoto Pearl Black Onyx Silver Cufflinks Set BoxFancy Big Vintage Elegant Black Onyx 14k Yellow Gold Size 7 Estate Huge Ring N/rMens Diamond & Black Onyx Ring White Gold Natural Round Cut Wedding Band Size 10Vintage Mexico Sterling Silver Onyx Necklace With Matching Earrings 98 Grams14kt Yellow Gold Jcm Faceted Onyx 1Vintage 925 Sterling Silver Black Onyx Chain Bracelet 7'' (13.5g) - 4164903 Vintage Sterling Silver Turquoise Inlay Onyx Coral Ring Lot Western NativeVintage Old Pawn Sterling Zuni Inlay Onyx Twist Spiral Spin Drop Dangle EarringsVintage Sterling Silver 925 Onyx Ring Size 5 Signed Mexico Modernistic Design Estate Diamond Black Onyx 14k Yellow Gold Wide Ring 9.7 Grams NrSize 5 1/2, Un-marked Vintage 14kt Yellow Gold Jewelry Ring, Black OnyxVintage Signed Zuni Silver Inlay Coral Onyx Turquoise Pearl Bolo Tie WesternLadies Vintage Navajo Sterling Silver Black Onyx Ring Size 6 Signed76 Grams! Turkish Ruby Topaz Onyx 925k Sterling Silver NecklaceVtg. Anitque Art Deco 10kt. Diamond And Onyx RingVictorian Mourning Cross 1-3mm Pearls Onyx Pendant (2368)Signed Lm Zuni Sterling Vintage Sterling Earring Onyx Mop Lapis Turquoise 2050Vintage Sterling Silver Unique Black Onyx Dangle Earrings (12.9g) - 415399Estate 8ct Natural Inlaid Set Black Onyx Sterling Silver Cuff Bracelet 16.9gSterling 925 Vintage Ring Lot Sz 6-8 Cz Onyx Topaz Gemstone Butterfly Heart 5239Gorham Gold Over Sterling Silver Black Onyx Unicorn Ring Sz 9.5 (5.5g) - 415811Vtg85g Bold Heavy Tigers Eye Onyx Taxco Mexico Mexican Sterling Silver BraceletAntique Art Deco Platinum Onyx Diamond Hat Scarf Pin,Massive Vtg 80s Haute Couture Black Onyx Resin Modernist Runway Cocktail Ring 8Vintage 925 Sterling Silver Black Onyx Open Eye Ball Ring Size 8 (5g) - 415915Lot Of 5 .925 Sterling Silver Mix Onyx Gemstone Pendants #p3105Vintage Mexican Sterling Silver Dangle Modernist Black Onyx NecklaceZuni Bracelet Silver Mosaic Inlay Thunderbird Turquoise Coral Onyx Mop - 37g10k White Gold Onyx And Diamond Vintage Ring NrHistoric 1932 St Louis College Of Pharmacy Class Ring-skull & Crossbones - 10k 1940's Vintage Man's 10k Yellow Gold Black Onyx And Diamond Ring