Blue Violet Tanzanite & Diamonds Halo Art Deco Style Statement Gold Ring
By Unbranded
Located in Tysons, VA
Ring Information Style: Art Deco Metal: Yellow Gold (White Top Diamond Part) Total weight: 3.50 g.
Diamond, Tanzanite, 14k Gold, White Gold, Yellow Gold
Art Deco Sapphire and Diamond Cocktail Ring in 18K Yellow Gold
Located in MONTMORENCY, FR
Step into the elegance of the Art Deco era with this exquisite cocktail ring, crafted in luxurious 18K yellow gold. Showcasing a captivating 0.75-carat sapphire at its center, flanke...
Diamond, Sapphire, 18k Gold, Yellow Gold
Art Deco 2.40 CTW No Heat Kashmir Sapphire Diamond Platinum Vintage Ring GIA
Located in Philadelphia, PA
Centering an oval cut sapphire weighing 0.92 carat - transparent medium vibrant blue in color Natural Kashmir in origin and displaying no indications of heat treatment - bezel set Wi...
Diamond, Sapphire, Platinum
$4,725Sale Price / item|25% Off
Art Deco Style Sapphire and Diamond Scalloped Engagement Ring in 18K Gold
Located in Bangkok, TH
This magnificent Art Deco sapphire ring centers a premium oval-cut blue sapphire enveloped by an intricate, wavy scalloped cluster of brilliant diamonds.
Diamond, Sapphire, Gold, 18k Gold, White Gold
Art Deco Style Pink Red Ruby & Diamond 18K White Gold Shield Ring
By Unbranded
Located in Tysons, VA
The setting is made of solid 18k white gold and every surface has been intricately engraved and carved into a beautiful homage to early Art Deco and Art Nouveau designs. Ring Inform...
Diamond, Ruby, 18k Gold, White Gold
Art Deco Style 8.8ct Natural Tanzanite Diamond Cocktail Ring 10k Rose Gold
Located in SYDNEY, AU
A very glamourous Art Deco style ring with a large 8.76 carat, oval faceted natural blue tanzanite claw set to an elongated panel, with twenty-eight bead set brilliant cut natural di...
Diamond, Tanzanite, 10k Gold, Rose Gold
Art Deco 14K White Gold Star Sapphire Ring with Diamond Accents, 1980
Located in Palm Desert, CA
This elegant ring is crafted in 14-karat white gold and features a captivating blue cabochon star sapphire measuring approximately 9 x 7 mm. Displaying a distinct six-rayed star, kno...
Diamond, Star Sapphire, White Gold
Price Upon Request
Oval Shaped Diamond Ring
Located in New York, NY
Stunning Three stone ring, amazing workmanship. The center Oval cut diamond is 4.52 CT. surrounded by fancy yellow diamonds. Along with 2.30 CT. total weight of oval shape diamond...
Diamond, 18k Gold
Art-Deco Original Platinum Green Tourmaline 2.20 cts. and Diamond Ring, Ca. 1920
Located in OVIEDO, AS
Art-Deco Original Platinum Green Tourmaline and Diamond Ring, Ca. 1920 This exquisite Art Deco ring showcases a vibrant oval-cut green tourmaline, measuring approximately (9.4 × 6.44...
Diamond, Tourmaline, Platinum
Art Deco Ceylon Sapphire and Diamond Flanked Solitaire Ring, circa 1920
Located in London, GB
Ceylon sapphire and diamond flanked solitaire ring. Set to centre with an oval old cut natural unenhanced Ceylon sapphire in an open back claw setting with an approximate weight of 7...
Diamond, Sapphire, 18k Gold, Platinum
Royal sapphire diamond halo art deco cocktail ring 18k white gold
Located in London, GB
Oval shaped sapphire blue vivid colour total weight 1.27ct Art deco style sapphire and baguette diamonds halo engagement ring in 18k white gold.
Diamond, Blue Sapphire, 18k Gold, White Gold
Art Deco 18kt Gold Onyx and Old Cut Diamond Ring, Circa 1920, Italy
Located in Firenze, IT
18 kt gold Art Deco onyx-diamond-ring, approx. 1920, oval ring head onyx, centered 1 old cut diamond approx. 0.40 ct ring shoulders in platinum with small diamond roses.
Diamond, Onyx, Platinum
Blue Sapphire & Diamond Vintage Inspired Art Deco Style 14K Yellow Gold Ring
By Unbranded
Located in Tysons, VA
An Art Deco inspired ring, set to center a bezel set oval natural blue sapphire, millgrain edging in typical Deco fashion, surrounded by triangle shaped sapphires at its side, top, a...
Diamond, Blue Sapphire, 14k Gold, Yellow Gold
Art Deco 2.00ct Sapphire and Diamond Trilogy Ring, c.1920s
Located in London, GB
An intense royal blue Sapphire sits between two old cut diamonds in this timeless Art Deco trilogy ring. The natural unheated sapphire is an oval cut stone weighing 2.00 carat.
Diamond, Sapphire, Platinum
Emerald & Ruby Diamond Vintage Inspired Art Deco Style Dinner Yellow Gold Ring
By Unbranded
Located in Tysons, VA
Eye catching and classically fashionable, it beautifully evokes the class and glamour of Art Deco design. 14K Yellow Gold. Ring Information Style: Art-deco Total Weight: 6.06 g.
Diamond, Emerald, Ruby, 14k Gold, Yellow Gold
Antique Art Deco Platinum Old Cut Sapphire No Heat Diamond Engagement Ring - GIA
Located in Great Neck, NY
Beautiful Antique Art Deco Platinum Old Cut Sapphire No Heat Diamond Engagement Ring - GIA. This gorgeous antique Art Deco no heat sapphire engagement ring is crafted in platinum. Th...
Diamond, Sapphire, Platinum
Blue Sapphire Diamond Edwardian Style Openwork Art Deco Inspired White Gold Ring
By Unbranded
Located in Tysons, VA
Ring Information Style: Art-deco Weight: 5.40 g.
Diamond, Blue Sapphire, 14k Gold, White Gold
$3,375Sale Price|25% Off
Ruby and Diamond Art Deco Style Dinner Ring in 18K White Gold
Located in Bangkok, TH
Ring Information Style: Art-deco Metal: 18K White Gold Weight: 6.11 g.
Diamond, Ruby, Gold, 18k Gold, White Gold
Art-Deco 15 carats Natural Aquamarine (No Treated) and Diamond in Platinum Ring
Located in OVIEDO, AS
Art-Deco neatr 15 carats Natural Aquamarine and Diamond in Platinum Ring.
Aquamarine, Platinum
Ruby and Diamond Art Deco Style Floral Ring in 14K White Gold
Located in Bangkok, TH
Ring Information Style: Art-deco Metal: 14K White Gold Total weight: 3.16 g.
Ruby, Diamond, 14k Gold, White Gold
Blue Sapphire Diamond Baguette Halo Art Deco Style Engagement Ring 14k Gold
Located in Bangkok, TH
Ring Information Style: Art Deco Metal: 14K White Gold Weight: 2.55 g.
Diamond, Sapphire, Blue Sapphire, Gold, White Gold, 14k Gold
Art Deco 1.15 Carat Pink Sapphire & .40 Carat Diamond Platinum Ring
Located in Scotts Valley, CA
Details: Fabulous alternative engagement or wedding ring! Stunning Art Deco period pink violet sapphire and diamond platinum ring.
Sapphire, Diamond, Pink Sapphire, Platinum
Fine Art Deco Madeira Citrine 18K Yellow Gold City Skyline Statement Ring
Located in New York, NY
Streamlined, sophisticated Art Deco period 18K gold City Skyline statement ring featuring a superb vivid golden orange oval facet cut citrine of excellent color and clarity.
Citrine, 18k Gold, Yellow Gold
18k Ring Solid Gold Ring Diamond Ring Emerald Ring Emerald Oval Ring Gold
By Oshi Jewels
Located in Bangkok, TH
18k Ring Solid Gold Ring Diamond Ring Emerald Ring Emerald Oval Ring Gold Fancy Ring This 18K solid white Gold Emerald / Diamond contemporary ring. The fine Quality gold fini...
Diamond, Emerald, Gold, Rose Gold
Art Deco Opal and Diamond 18 Carat Gold Cocktail Ring
Located in Chipping Campden, GB
The opal is pale in colour and has lots of flashes of green and all other colours within it. The old mine cut diamonds surrounding the opals total 42pts. The ring itself is modelled...
Diamond, Opal, Gold
$2,400Sale Price|25% Off
Ruby and Diamond Art Deco Style Engagement Ring in 14K White Gold
Located in Bangkok, TH
Ring Information Style: Art-deco Metal: 14K White Gold Total weight: 4.35 g.
Diamond, Ruby, White Gold, 14k Gold
Art Deco 4.05 Carat Ruby and Old Euro Diamond Halo Platinum Ring - AGL Certified
Located in Miami, FL
Vintage Art Deco original platinum ring featuring a 4.05-carat oval cut Thai ruby, certified by AGL.
Diamond, Ruby, Platinum
$2,450Sale Price|30% Off
Pink Tourmaline Sapphire Diamond Art Deco Style Target Engagement Ring in 14K
Located in Bangkok, TH
A vivid masterpiece reflecting the daring chromatic choices of the jazz age, this stunning Art Deco inspired target ring is an absolute showstopper.
Diamond, Sapphire, Tourmaline, 14k Gold, White Gold, Gold
Green Tourmaline Ruby & Diamond Art Deco Style Halo 14K Yellow Gold Ring
By Unbranded
Located in Tysons, VA
Ring Information Style: Art-deco Metal: 14K Yellow Gold Total weight: 3.34 g.
Diamond, Ruby, Tourmaline, 14k Gold, Yellow Gold
Green Emerald & Red Ruby Diamond Art Deco Style 18 Yellow Gold Ring
By Unbranded
Located in Tysons, VA
Ring Information Style: Art-deco Metal: 18K Yellow Gold Total weight: 5.41 g.
Diamond, Emerald, Ruby, 18k Gold, Yellow Gold
Art Deco Amethyst Solitaire Filigree Ring in Two Tone 14 Karat Gold
Located in Boston, MA
An Art Deco period Amethyst filigree solitaire ring. Centered by a rich vivid purple amethyst of 6.00 Carats. Accented by filigree scroll work through and engraved detailing. Hallm...
Amethyst, Gold, 14k Gold
Art Deco 2.15 Ct Sapphire 1.0 Ct Diamond 18 KT Platinum Ring
Located in Napoli, IT
This appealing Sapphire & Diamond Art Deco ring, is 1920 ca. Appealing timeless design rendered in a skilfully hand crafted mount of solid 18 kt gold and Platinum Hand crafted moun...
Diamond, Sapphire, 18k Gold, Platinum
925 Sterling Silver 1.5 ct Oval Moissanite Ring Oval Shaped Engagement Ring.
Located in Chicago, IL
925 Sterling Silver 1.5 ct Oval Moissanite Ring Oval Shaped Engagement Ring. Gemstone: Natural Moissanite Gemstone size: Center Stone - 6mm x 8 mm Stone Weight- 1.5 cts Gem colour: ...
Silver, Sterling Silver
Antique Art Deco Sapphire & Diamond Three-Stone Filigree Engagement Ring
Located in Santa Barbara, CA
Condition: Very good Era: Art Deco Year: 1915-1935 Metal: 18k White Gold Diamonds: (2) Carat Weight: 1.84 Total (0.76 + 1.08) Cut: Old European Color Range: G-I Clarity: SI1 Gemsto...
Diamond, Sapphire, Gold, 18k Gold, White Gold
2.45 Carat Coral Diamond 14 Karat Gold Art Deco Style Ring
By Meghna Jewels
Located in Hoffman Estate, IL
This ring has been meticulously crafted from 14-karat gold. It is hand set with .70 carats diamond and 2.45 carats coral. The ring is a size 7 and may be resized to larger or sm...
Coral, Diamond, Gold, 14k Gold
Art Deco Style Platinum Diamond 3.73 Carat Australian Black Opal Engagement Ring
Located in Los Angeles, CA
Latest of my creations. A breathtaking Art Deco Inspired Australian Black Opal Baguette Diamond Engagement Ring Handmade in 90% Platinum.
Diamond, Opal, Black Opal, Platinum
Ruby and Diamond Art Deco Style Engagement Ring in 18K White Gold
Located in Bangkok, TH
This Art Deco-style engagement ring features a bold ruby at the center, framed by diamonds that curve over each corner.
Ruby, Diamond, 18k Gold, White Gold
Art Deco Style Pink Red Ruby & Diamond Cocktail 18K White Gold Statement Ring
By Unbranded
Located in Tysons, VA
Art Deco style ring ruby and diamonds inlaid in form of bringing a sparkling look that accentuate the prismatic color of the oval ruby in center.
Diamond, Ruby, 18k Gold, White Gold
$1,680Sale Price|20% Off
Vintage 18k Yellow Gold Art Deco Citrine and Diamond Ring, 5.05ct
Located in New York, NY
Vintage 18k Yellow Gold Citrine and Diamond Ring Make a bold statement with our stunning 18k yellow gold citrine and diamond ring. At the center, a magnificent oval citrine weighing...
Citrine, Diamond, 18k Gold, Yellow Gold
Blue Sapphire Diamond Art Deco Style Halo Ring in 14K White Gold
Located in Bangkok, TH
This white gold ring is typical of the Art Deco period. It is mixture of a target and cluster design.
Diamond, Blue Sapphire, 14k Gold, White Gold
Yellow Gold Oval Diamond Dome Ring
Located in New York, NY
Yellow Gold Oval Diamond Dome Ring Description: This 18K yellow gold ring showcases a bright 1.06-carat oval diamond framed by a full dome of shimmering round diamonds, creating a b...
Diamond, White Diamond, Gold, 18k Gold, Yellow Gold
Art Deco Style Pink Red Ruby & Diamond 18K White Gold Dome Bombe Ring
By Unbranded
Located in Tysons, VA
Ring Information Style: Art-deco Metal: 18K White Gold Total weight: 6.04 g.
Diamond, Ruby, 18k Gold, White Gold
Emerald Diamond Art Deco Style Halo Engagement Ring in 14K White Gold
Located in Bangkok, TH
Ring Information Style: Art-deco Metal: 14K White Gold Total weight: 3.36 g.
Diamond, Emerald, Gold, White Gold, 14k Gold
$2,742Sale Price|20% Off
Vintage Yellow Gold Sapphire and Diamond Art Deco Style Cocktail Ring
Located in Monte Carlo, MC
An elegant rectangular sapphire and diamond ring, crafted in a two-tone design, predominantly yellow gold with refined white gold accents around selected diamonds. The ring features ...
Sapphire, Blue Sapphire, Diamond, Yellow Gold, 18k Gold, Gold
Art Deco Ruby Diamond Platinum Ring, Calibré-Cut Ruby Panel, circa 1930´s
Located in OVIEDO, AS
A striking and finely composed Art Deco ring, dating to circa 1930´s, showcasing a richly coloured natural ruby set within an elegant geometric platinum mount.
Diamond, White Diamond, Ruby, Platinum
GIA Certified 9.46 Carat Green Cats Eye Chrysoberyl 14K Gold Art Deco Ring
Located in Miami, FL
Product Specifications: Item Type: Vintage Cats Eye Ring Metal: 14K Yellow Gold Size: 6.5 (adjustable) Weight: 3.94 grams (setting alone) Certificate: GIA #1535675891 Style: Art Deco...
Chrysoberyl, Gold, 14k Gold, Yellow Gold
Amethyst Emerald Diamond Art Deco Style Cocktail Ring in 14K Yellow Gold
Located in Bangkok, TH
A vibrant oval Amethyst takes center stage in this Art Deco–inspired cocktail ring.
Diamond, Amethyst, Emerald, Gold, 14k Gold, Yellow Gold
Emerald Onyx Diamond Art Deco Style Halo Ring in 18K White Gold
Located in Bangkok, TH
Ring Information Style: Art-deco Metal: 18K White Gold Total weight: 4.37 g.
Diamond, Emerald, Onyx, 18k Gold, White Gold
Art Deco Nine Carat Amethyst Ring 14 Karat White Gold Antique Filigree
Located in New York, NY
This is an extraordinary antique Art Deco Amethyst 14 Karat White Gold Ring with a stunning oval faceted natural Amethyst of approximately 9.2 Carats in a gorgeous filigree open work...
Amethyst, Gold, 14k Gold, White Gold
Garnet and Diamond Art Deco Style Engagement Ring in 14K Yellow Gold
Located in Bangkok, TH
A rich Garnet takes center stage in this Art Deco–inspired step ring, glowing with deep, captivating warmth.
Diamond, Ruby, Garnet, Gold, 14k Gold, Yellow Gold
$3,706Sale Price|44% Off
Tanzanite Gold Ring Vivid Blue Oval Cut Engagement ring
Located in Berlin, DE
14K white gold ring with natural Tanzanite and Diamonds tanzanite origin - Tanzania tanzanite measurements - 0.12 x 0.16 x 0.24 in / 3 х 4 х 6 mm tanzanite weight - 0.48 carats, colo...
Diamond, Tanzanite, Gold, 14k Gold, White Gold
Antique Art Deco 14K Yellow Gold Amethyst and Onyx Engraved Cocktail Ring
Located in Great Neck, NY
Beautiful Antique Art Deco 14K Yellow Gold Amethyst and Onyx Engraved Cocktail Ring.
Amethyst, Diamond, Onyx, Gold, 14k Gold, Yellow Gold
3 Carat Art Deco Bohemian Garnet Ring Gold Antique Wedding Engagement Cocktail
Located in New York, NY
This is a gorgeous Are Deco Bohemian Garnet Ring with a stunning oval faceted blood red garnet of approximately 3 Carats set in 10 Karat Gold. The Garnet is an exquisite blood red c...
Garnet, Gold, Yellow Gold, 10k Gold
Opal Emerald Diamond Halo Art Deco Style Engagement Ring in 14K Yellow Gold
Located in Bangkok, TH
Ring Information Style: Art Deco Metal: 14K Yellow Gold Weight: 3.25 g.
Diamond, Emerald, Opal, Gold, Yellow Gold, 14k Gold
$4,050Sale Price|25% Off
Emerald Diamond Art Deco Style Cushion Shape Engagement Ring in 18K White Gold
Located in Bangkok, TH
An exquisite manifestation of geometric refinement, this breathtaking Art Deco inspired cluster engagement ring showcases a vivid, oval-cut emerald at its core.
Emerald, Diamond, White Gold, 18k Gold, Gold
Red Pink Ruby & Diamond Pave Set Art Deco Style Cocktail White Gold Ring
By Unbranded
Located in Tysons, VA
Ring Information Style: Art-deco Metal: 18K White Gold Total weight: 7.88 g.
Diamond, Ruby, 18k Gold, White Gold
Diamond & Ruby Art Deco Style Halo Set Vintage Inspired 14K White Gold Ring
By Unbranded
Located in Tysons, VA
Eye-catching and classically fashionable. 14K White Gold. Ring Information Style: Art-deco Weight: 4.00 g.
Diamond, Ruby, 14k Gold, White Gold
Art Deco Platinum Sapphire and Old Cut Diamond Ring
Located in Braintree, GB
An Art Deco ring crafted in platinum, centred with an oval natural sapphire within a double border of old cut diamonds.
Diamond, Blue Sapphire, 18k Gold
Art Deco 18k Gold Platinum Ruby Diamond Bypass Engagement Ring, 2.32ct
Located in Brunswick, ME
Untreated Ruby and Diamond Vintage Engagement Bypass 18k gold and platinum Ring Natural 100% ruby antique oval cut 1.60 carats, cherry-red excellent color and brilliance, country of...
Ruby, Diamond, Yellow Gold, Platinum, 18k Gold
$1,632Sale Price / item|20% Off
Art Nouveau Inspired Oval Cut Blue Sapphire Cluster Ring Made in 18k White Gold
By VR Jewels
Located in New York, NY
Art Nouveau Inspired Oval Cut Blue Sapphire Cluster Ring Made in 18k White Gold featuring natural sapphire of 3.72 carats. The gorgeous handcrafted ring goes with every style. Sapphi...
Blue Sapphire, Gold, 18k Gold, White Gold
Fascination with the Jazz Age is endless, and even today jewelry designers continue to be inspired by authentic Art Deco jewelry and watches.
The Art Deco period, encompassing the 1920s and ’30s, ushered in a very distinct look in the design of jewelry. There were many influences on the jewelry of the era that actually began to take shape prior to the 1920s. In 1909, Serge Diaghilev brought the Ballet Russes to Paris, and women went wild for the company’s exotic and vibrant costumes It’s no wonder, then, that jade, lapis lazuli, coral, turquoise and other bright gemstones became all the rage. There already existed a fascination with the East, particularly China and Japan, and motifs consisting of fans and masks started to show up in Art Deco jewelry.
However, the event that had the greatest influence on Deco was the excavation of the tomb of King Tut in 1922. When the world saw what was hidden in Tut’s burial chamber, it sent just about everyone into a frenzy. Pierre Cartier wrote in 1923 that “the discovery of the tomb will bring some sweeping changes in fashion jewelry.” And he couldn’t have been more right. “Egyptomania” left an indelible mark on all of the major jewelry houses, from Cartier to Van Cleef & Arpels, Boucheron and Georges Fouquet. (Cartier created some of the most iconic jewelry designs that defined this era.)
While a lot of Art Deco jewelry was black and white — the black coming from the use of onyx or black enamel and the white from rock crystal and diamonds — there is plenty of color in jewelry of the era. A perfect accent to diamonds in platinum settings were blue sapphires, emeralds and rubies, and these stones were also used in combination with each other.
Many designers employed coral, jade and lapis lazuli, too. In fact, some of the most important avant-garde jewelers of the period, like Jean Després and Jean Fouquet (son of Georges), would combine white gold with ebony and malachite for a jolt of color.
A lot of the jewelry produced during this time nodded to current fashion trends, and women often accessorized their accessories. The cloche hat was often accented with geometric diamond brooches or double-clip brooches. Backless evening dresses looked fabulous with sautoir necklaces, and long pearl necklaces that ended with tassels, popular during the Edwardian period, were favored by women everywhere, including Coco Chanel.
Find unique Art Deco necklaces, earrings, bracelets and other jewelry on 1stDibs.
Antique and vintage rings have long held a special place in the hearts of fine jewelry lovers all over the world.
No matter their origin or specific characteristics, rings are timeless, versatile accessories. They’ve carried deep meaning since at least the Middle Ages, when diamond rings symbolized strength and other kinds of rings were worn to signify romantic feelings or to denote an affiliation with a religious order. Rings have also forever been emblematic of eternity.
Over time, rings have frequently taken the form of serpents, which have long been associated with eternal life, health and renewal. Italian luxury jewelry house Bulgari has become famous for its widely loved Serpenti motif, for example, and its Serpenti ring, like the other accessories in the collection, began as an homage to jewelry of the Roman and Hellenistic eras. The serpent is now a popular motif in fine jewelry. Jewelry devotees have long pined for rings adorned with reptiles, thanks to antique Victorian rings — well, specifically, Queen Victoria’s illustrious engagement ring, which took the form of a gold snake set with rubies, diamonds and an emerald (her birthstone). Designs for Victorian-era engagement rings often featured repoussé work and chasing, in which patterns are hammered into the metal.
Engagement rings, which are reliably intimidating to shop for, are still widely recognized as symbols of love and commitment. On 1stDibs, a range of buying guides can be found for those in the market for antique engagement rings, vintage engagement rings or Art Deco engagement rings.
The most collectible antique engagement rings and vintage engagement rings are those from the Victorian, Edwardian and Art Deco eras. Named for the monarchies of the four King Georges, who in succession ruled England starting in 1714 (plus King William’s reign), antique Georgian rings, be they engagement rings or otherwise, are also coveted by collectors. Pearls, along with colored gemstones like garnets, rubies and sapphires, were widely used in Georgian jewelry. The late-1700s paste jewelry was a predecessor to what we now call fashion or costume jewelry.
The Art Nouveau movement (1880–1910) brought with it rings inspired by the natural world. Antique Art Nouveau rings might feature depictions of winged insects and fauna as well as women, who were simultaneously eroticized and romanticized, frequently with long flowing hair. Art Deco jewelry, on the other hand, which originated during the 1920s and ’30s, is by and large “white jewelry.” White metals, primarily platinum, were favored over yellow gold in the design of antique Art Deco rings and other accessories as well as geometric motifs, with women drawn to the era’s dazzling cocktail rings in particular.
Whether you’re hunting down a chunky classic for a Prohibition-themed cocktail party or seeking a clean contemporary design to complement your casual ensemble, find an exquisite collection of antique, new and vintage rings on 1stDibs.
Learn about these antique jewelry styles, then choose a design that speaks to you.
Ready to rock? Some of our favorite jewelry designers and dealers share indispensable advice for choosing that most important ring.
Will your beloved be enchanted by an Edwardian ring or a trendy Art Deco piece? We clue you into period styles and tips for finding the perfect ring.