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    

Rare Antique Victorian 10k Gold Onyx Pearl Aei Eternal Love Dangle EarringsVintage 1920's Art Deco Czech Peking Onyx Glass Enamel Flower Bangle BraceletRare Antique Victorian 14k Gold Onyx Seed Pearl Aei Eternal Love Memento LocketAntique Victorian Mourning 14k Gold Onyx Seed Pearl Pendant NecklaceDavid Yurman 14k Sterling Silver Onyx Hampton Bracelet Signed Dy 585 925Vintage Silpada Sterling Silver Black Faceted Onyx Ornate Pendant (22.7g)-209129Old Pawn Navajo Vintage Sterling Black Onyx Unique Cigar Band Handmade Ring Sz 8Vintage 14k Yellow Gold Pendant/enhancer With Onyx, Mabe Pearl And Diamonds! Q3Vintage Navajo Sterling Silver Leaf Applique & Black Onyx Ring Sz 7 ”Vintage 925 Sterling Silver Black Onyx Elizabeth And James Fox Pendant Necklace35 Pc Lot Vintage Lockets & Pendant Necklaces - Cameo Opal Onyx CloisonneVintage Mexico Sterling Silver Black Onyx Inlay Link Bracelet Size 7Vintage Important Etruscan Onyx & Carnelian & Jade Glass Necklace & EarringsAntique Art-deco, Egyptian Revival Copper & Onyx- Winged Scarab Amulet NecklaceWilson Padilla Navajo Vintage Large Heavy Sterling Silver & Onyx Cuff BraceletAntique Onyx Seed Pearl 14k Gold Oval Dragonfly Earrings 8.3 Grams NrVintage Big Heavy 25.7g Onyx Solid Sterling Silver Ring Unisex Mens Biker EstateSterling Silver - Art Deco Faceted Black Onyx 5.6g - Ring (7) Ed8151Vintage Mexico Taxco Sterling Silver Modernist Black Onyx Post Earrings Tc-138Old Art Deco Taxco Mexico Silver Onyx Link Panel Choker Necklace Bracelet LotSterling Silver 925 Vintage Necklace Pendant Lot Onyx Flower Turquoise Native! 5Vintage Mexico Taxco Sterling Silver Turquoise Onyx Inlay Bracelet Size 7 Tb-16Vintage 925 Sterling Silver Black Onyx Navajo Tear Drop Earrings - 352244Vintage Mexico Taxco Sterling Silver Brass Twisted Cuff Black Onyx Cuff BraceletAntique Mid-19thc Gold Mourning Brooch Pins Hair Jewelry W/ Onyx & Coral NrVintage Sterling Silver & Black Obsidian/onyx? Mayan Aztec Face Mask NecklaceVintage Navajo Indian Sterling Silver Gold Wash Turquoise Onyx Mop Inlay WatchStunning Huge 80g 2 3/4" Vtg Onyx Navajo Man's Silver Plate Cuff Bracelet Ni281Vintage Mexico Mws 950 Sterling Silver Black Onyx Inlay Link Bracelet 30.4gEstate 14k Yellow Gold Black Onyx Oval Cabochon Opal Ring Weight 3.1 Dwt Vtg NrBlack Onyx & Diamond Ring 14k Yellow Gold Estate Vintage Natural Emerald CutRare Retro 3 Tone Solid Gold, Black Onyx & Diamond, Art Deco Lady's Estate RingVintage Fancy 8.15 To 17.9mm Pink Coral & Onyx Bead Graduated Strand NecklaceVintage Camphor Glass Natural Moonstone Onyx Sterling Silver Filigree Ring1930's Vintage 14k White Gold European Cut Diamond And Onyx Hand Carved RingVintage Mens Sterling Silver And Gold Carved Carnelian Roman Soldier Onyx RingVintage 2 Sterling Silver Turquoise Lapis Malachite Onyx Pendant NecklaceVintage Chunky 62 Grams Taxco Mexico Mexican Sterling Silver Black Onyx BraceletVintage Mexico Taxco Sterling Silver Black Onyx Cuff Bracelet Size 5 Th-15 321Vintage 925 Sterling Silver Anique Finish Black Onyx Marcasite Drop Earrings 11gFine Black Onyx Inlay Band 14k Yellow Gold Natural Bright Polish RingAntique Victorian Vintage Gold Filled Cameo Locket Onyx Engraved Wow 4134Vintage 925 Sterling Silver Black & Red Onyx Marcasite Ring Size 7 - 353041Vintage Sterling Silver - Signed .925 Black Onyx & Marcasite Pendant 6.6gVintage Designer Signed Christian Dior 80's Crystal Onyx Rhinestones Earrings NrVtg Mexico Sterling Silver & Onyx Oval Hinged Bangle Bracelet Taxco 35 GramsVintage Sterling Silver Black Onyx 6.75" Linked Bracelet (56.6g) - 347107Vintage 925 Sterling Silver Unique Black Onyx Chain Bracelet - 352357Vintage Solid 9ct Gold Gents Onyx RingVintage Faceted Green Onyx Marcasite Chain .800 Silver 15" NecklaceAntique Vintage Art Deco Onyx And Diamond Ring Circa 1920Art Deco Onyx Marcasite Pear Shape EarringsVictorian Big Fancy Glamerus Bracelet Unusual Big Black Onyx 100 Yrs Old OddVintage 925 Sterling Silver Black Onyx Graduated Tiered Ring Size 7 - 353023Vintage 925 Sterling Silver Antique Finish 2-tone Black Onyx Wrap Ring 10gVintage 925 Sterling Silver Black Onyx Oval Push Back Earrings - 352243Vintage Mexico Taxco Sterling Silver Triple Channel Black Onyx Cuff BraceletAntique Art Deco Diamond Turquoise Pearls & Onyx Tassel Drop Pendant 5.4 GramsVintage 10k Gold And Onyx Ring--3.39 Gr.Old Pawn Vintage Navajo Zuni Sterling Turquoise Opal Blk Onyx Inlay Men's Ring