Set in 18K white Gold, 22.46 carat Aquamarine, Emerald & Diamond Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Aquamarine & Emerald "Kissing" Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Aquamarine is 22.46 carats. Th...
Aquamarine, Diamond, Emerald, 18k Gold, White Gold
Set in 18K Gold, Blue Sapphire, Emerald & Diamonds "Kissing" Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Blue Sapphire & Emerald "Kissing" Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Emerald is 8.19 carats. The...
Diamond, Emerald, Blue Sapphire, 18k Gold, White Gold
Set in 18K white Gold, Zambian Emerald, Pink Sapphire & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Emerald & Pink Sapphire Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Emerald is 5.65 carats. The Emerald i...
Diamond, Emerald, Pink Sapphire, 18k Gold, White Gold
Set in 18K White Gold, 1.47 carats, Tanzanite & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Tanzanite Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Tanzanite is 1.47 carats. The Tanzanite is resp...
Diamond, Tanzanite, 18k Gold, White Gold
Set in 18K Gold, Aquamarine, Green Enamel & Diamonds Art Deco Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Aquamarine & Green Enamel Engagement Cocktail Ring set in 18K White Gold & natural Diamonds. The weight of the Aquamarine is 5.38 carats....
Aquamarine, Diamond, 18k Gold, Enamel
Set in 18K white Gold, 2.39 carat Rubellite & Diamonds "Kissing" Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Rubellite "Kissing" Engagement Ring set in 18K White Gold and natural Diamonds. The weight of the pear shaped Rubellite is 2.39 carats. T...
Diamond, Rubelite, 18k Gold, White Gold
Set in 18K Gold, Zambian Emerald, Mozambique Ruby & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Emerald & Ruby "Kissing" Engagement Ring set in 18K White Gold and natural Diamonds. The weight of the Emerald is 7.25 carats. The Emeral...
Diamond, Emerald, Ruby, 18k Gold
Set in 18K Gold, natural, Mozambique Ruby, Black Onyx & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Art Deco style, Ruby & Black Onyx Engagement Cocktail Ring set in 18K White Gold & natural Diamonds. The weight of the Ruby is 1.13 carats. The Ruby is...
Diamond, Onyx, Ruby, 18k Gold
Set in 18K Yellow Matte Gold, natural Zambian Emerald & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Art Deco style, Emerald Engagement Ring set in 18K Yellow Matte Gold & natural Diamonds. The weight of the Emerald is 2.15 carats. The Emerald is compl...
Diamond, Emerald, Gold, 18k Gold
Set in 18K Gold, 27.67 carat, Zambian Emerald & Rose Cut Diamond Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Emerald Engagement Cocktail Ring set in 18K White Gold & natural Diamonds. The weight of the Emerald is 26.67 carats. The Emerald is comp...
Diamond, Emerald, 18k Gold, White Gold
Set in 18K Rose Gold, Kunzite, Black Onyx & Diamonds Art Deco Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Art Deco style, Kunzite & Black Onyx Engagement Ring set in 18K Rose Gold & natural Diamonds. The weight of the Kunzite is 7.24 carats. The weight of t...
Diamond, Kunzite, Onyx, 18k Gold, Rose Gold
Set in 18K Gold, 3.29 carat, Tanzanite, Orange Enamel & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Tanzanite & Orange Enamel Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the shield cut Tanzanite is 3.20 carats...
Diamond, Tanzanite, 18k Gold, Enamel
Set in 18K white Gold, Emerald Sugarloaf, Green Enamel & Diamond Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Emerald & Green Enamel Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Emerald Sugarloaf is 12.98 carats. The...
Diamond, Emerald, 18k Gold, White Gold, Enamel
Luxury 14KT Gold Red Garnet Overlapping Infinity Ring
By Artisan NYC
Located in New York, NY
Discover the perfect harmony of fluid design and fiery brilliance with this 14KT gold twist band. Featuring a graceful, overlapping infinity silhouette, this ring is meticulously pav...
Garnet, Gold, 14k Gold
Set in 18K Gold, 10.84 carat Tanzanite, Mozambique Ruby & Diamonds Cocktail Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Tanzanite & Ruby Engagement Cocktail Ring set in 18K White Gold & natural Diamonds. The weight of the Tanzanite is 10.84 carats. The Tanz...
Diamond, Ruby, Tanzanite, 18k Gold
Set in 18K Gold, 2.78 carat, natural Zambian Emerald & Diamond Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Emerald Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Emerald is 2.78 carats. The Emerald is completely nat...
Diamond, Emerald, 18k Gold
Exquisite 1.8ct Garnet and 0.43ct Diamond 14KT Gold Statement Ring
By Artisan NYC
Located in New York, NY
A Symphony of Crimson and Sparkle Make a bold impression with this stunning statement ring, a masterclass in jewelry craftsmanship that blends vibrant color with timeless brilliance...
Diamond, Garnet, Gold, 14k Gold, Rose Gold
14k Gold Emerald Diamond Solitaire Ring 1.40 Ct Zambian Emerald with DiamondRing
Located in Jaipur, IN
**Zambian Emerald Ring, Emerald and Diamond Ring, 14K Yellow Gold Emerald Statement Ring, Unique Designer Jewelry** Showcasing the timeless beauty of a vivid natural Zambian emerald...
Diamond, Emerald, 14k Gold, Yellow Gold
Set in 18K white Gold, 3.93 carats Tanzanite & Rose Cut Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Tanzanite Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Tanzanites is 3.93 carats. The Tanzanites are respo...
Diamond, Tanzanite, 18k Gold, White Gold
Set in 18K white Gold, 1.66 carats Yellow Sapphire & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Yellow Sapphire Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Yellow Sapphire is 1.66 carats. The Yellow Sa...
Diamond, Yellow Sapphire, 18k Gold, White Gold
Set in 18K Gold, Mozambique Ruby, Pink Sapphires & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Ruby & Pink Sapphires Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Ruby is 0.91 carats. The Ruby ...
Diamond, Ruby, Pink Sapphire, 18k Gold
Set in 18K Gold, Zambian Emerald, Blue Enamel & Diamond Art Deco Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and very beautiful, Art Deco style, Emerald & Enamel Cocktail Engagement Ring set in White Gold & natural Diamonds. The weight of the Emerald is 6.10 carats. The Emer...
Diamond, Emerald, 18k Gold, Enamel
14K Yellow Gold 0.68 CT Natural Diamond Multi-Row Domed Pave Band Ring
Located in Jaipur, IN
A dome of pure diamond brilliance — this 14K solid yellow gold band ring covers its wide, sculptural domed face entirely in multi-row micro-pavé natural diamonds. 0.68 carats of cont...
Diamond, 14k Gold, Yellow Gold
Set in 18K white Gold, Morganite, Emerald & Diamonds "Kissing" Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Morganite & Emerald "Kissing" Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Morganite is 5.90 carats. The w...
Morganite, Emerald, Diamond, White Gold, 18k Gold
Solid 14k Yellow Gold Pear Cut Emerald Gemstone Stackable Dainty Minimalist Ring
Located in Jaipur, IN
This is a Yellow Gold Bezel-Set Pear Emerald Beaded Ring featuring a delicate, minimalist design with contrasting textures Details:- Item Code :- RIMJOS-742 Material - 14K Solid Yel...
Emerald, 14k Gold, Yellow Gold
Set in 18K white Gold, 4.22 carat Tourmaline & Baguette Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Tourmaline Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Tourmaline is 4.22 carats. The combined Diamonds w...
Diamond, Tourmaline, 18k Gold, White Gold
$1,200Sale Price|20% Off
Set in 18K white Gold, Ceylon Multi Sapphires & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and dainty, modern style, Multi Sapphires Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Multi Sapphires is 0.16 carats. The Multi Sapphi...
Diamond, Sapphire, Blue Sapphire, Pink Sapphire, Yellow Sapphire, 18k Go...
$7,680Sale Price|20% Off
Set in 18K Gold, 3.99 carats, Zambian Emerald & Yellow Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern stye, Emerald Engagement Ring set in 18K Yellow Gold & natural Diamonds. The weight of the Emerald is 3.99 carats. the Emerald is completely nat...
Yellow Diamond, Emerald, 18k Gold
Certified Natural Emerald Band White Gold Vermeil cocktail Ring
Located in Delhi, DL
Natural emerald natural Diamond white gold Vermeil ring / Band consists of: Gross weight- 10.200grams Metal- Silver Metal purity- 925 sterling silver Metal color- White gold Vermeil ...
Emerald, Gold Plate, White Gold, Vermeil, Sterling Silver
Moissanite Toi et Moi Heart Pear Ring 925 Silver Duo Ring Unique Women Ring.
Located in Chicago, IL
Moissanite Toi et Moi Heart Pear Ring 925 Silver Duo Ring Unique Women Ring. "You And Me Ring" Base Material: 925 Sterling Silver. Main Stone: Moissanite. Moissanite Color & Cl...
Silver, Sterling Silver
Set in 18K Gold, Zambian Emerald, Black Enamel & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Emerald & Black Enamel Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Emerald is 1.43 carats. The Emerald is...
Diamond, Emerald, 18k Gold, Enamel
$2,640Sale Price|20% Off
Set in 18K Gold, 3.66 carats Morganite & Emerald cut Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Morganite Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Morganite is 3.66 carats. The combined Diamonds wei...
Diamond, Emerald, Morganite, 18k Gold
$292Sale Price|35% Off
IGI Certified Natural uncut rose cut Diamond sterling silver eternity band Ring
Located in Delhi, DL
-Diamond type- Natural rose cut, natural uncut diamond -Diamond color- white with a tint of grey -Diamond weight- 2.50ctw -Metal- 925 Sterling silver Metal color- oxidized silver...
Diamond, Sterling Silver
$2,800Sale Price|20% Off
Set in 18K Gold, 2.14 carats natural Zambian Emerald & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Emerald Engagement Ring set in 18K Gold White Gold & natural Diamonds. The weight of the Emerald is 2.14 carats. The Emerald is completely natural, wit...
Diamond, Emerald, 18k Gold
$2,560Sale Price|20% Off
Set in 18K Gold, Invisible set Rubies, Yellow Diamond & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Ruby & Yellow Diamond Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the invisible set Rubies is 1.42 carats. Th...
Yellow Diamond, Ruby, 18k Gold
2.55ct Pink Lab Heart Diamond Double Halo Ring 14K White Gold Anniversary Ring
Located in Jaipur, IN
The pink cocktail ring in lab-grown diamonds. Fancy pink heart cut at centre, white diamond inner halo, pink diamond outer halo, five-row mixed pink and white pavé dome band. All in ...
Diamond, Pink Diamond, 14k Gold, White Gold
$2,400Sale Price|20% Off
Set in Platinum 900, 4.69 Carats Aquamarine & Diamonds Engagement Cocktail Ring
Located in Hong Kong, HK
A very gorgeous and classical, Aquamarine Engagement / Wedding Ring set in Platinum 900 & Diamonds. The weight of the Emerald Cut Aquamarine is 4.69 carats. The weight of the Diamond...
Aquamarine, Diamond, Platinum
Set in 18K white Gold, Ruby, Tourmaline, Black Enamel & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Art Deco style, Ruby, Tourmaline & Black Enamel Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Tourmaline is 0.91 carats. ...
Diamond, Ruby, Tourmaline, 18k Gold, White Gold, Enamel
$5,440Sale Price|20% Off
Set in 18K Gold 10.85 carats Zambian Emerald & Rose Cut Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful Emerald Engagement Ring set in 18K White Gold & Diamonds. The weight of the Emerald is 10.85 carats. The Emer...
Diamond, Emerald, 18k Gold
Rare Natural Nishapuri Iranian turquoise 925 silver shajari firoza handmade Ring
Located in Delhi, DL
-Metal- 925 Sterling silver - Metal color- silver -Gemstone- Turquoise (Natural) - Gemstone origin- Nishapuri firoza, Iranian turquoise, - Gemstone type- Shajari firoza/turquoise
Turquoise, Sterling Silver, Silver
$4,560Sale Price|20% Off
Set in 18K Gold, 2.72 carats, natural Zambian Emerald & Diamond Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Emerald Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Emerald is 2.72 carats. The Emerald is completely natural, without ...
Diamond, Emerald, 18k Gold, White Gold
$336Sale Price|20% Off
IGI Certified Natural uncut rose cut Diamond sterling silver Statement Ring
Located in Delhi, DL
-Diamond type- Natural rose cut, natural uncut diamond -Diamond color- white with a tint of grey -Diamond weight- 2.25ctw -Metal- 925 Sterling silver Metal color- oxidized silver...
Diamond, Sterling Silver
$2,560Sale Price|20% Off
4.00 Carats, Natural Zambian Emerald & Rose Cut Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and one of a kind, Emerald Engagement / Cocktail Ring set in 18K White Gold & Diamonds. The weight of the Emerald is 4.00 carats. The Emerald is completely natural wi...
Diamond, Emerald, 18k Gold
$2,244Sale Price|20% Off
14KT Gold Aries Zodiac Diamond Signet Ring
By Artisan NYC
Located in New York, NY
A bold tribute to the first sign of the zodiac, this Aries signet ring is a fusion of celestial symbolism and timeless luxury. Masterfully crafted in solid 14KT yellow gold, the ring...
Diamond, 14k Gold, Gold, Yellow Gold
Set in 18K Gold, 15.63 carats, Zambian Emerald & Yellow Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and important, modern style, Emerald Engagement Ring set in 18K Yellow Gold & natural Diamonds. The weight of the Emerald is 15.63 carats. The Emerald is complete...
Yellow Diamond, Emerald, 18k Gold, Yellow Gold
$8,912Sale Price|20% Off
Artisan Tanzanite And Diamond Cocktail Ring 18K White Gold
By Artisan NYC
Located in New York, NY
This stunning cocktail ring by Artisan features a vivid 5.94ct square-cut tanzanite surrounded by 1.90ct of sparkling diamonds, all set in 4.623g of 18K white gold. The bold cluster ...
Diamond, Tanzanite, 18k Gold, White Gold
14 Karat Gold Green Tourmaline Rubellite Pink Tourmaline Baguette Diamond Ring
By Vaibhav Dhadda
Located in Jaipur, Rajasthan
18 karat gold green tourmaline rubellite pink tourmaline baguette diamond ring. This extraordinary deep forest green tourmaline and r...
Diamond, Rubelite, Tourmaline, Gold, 18k Gold, Yellow Gold
Solid 14k Yellow Gold Jewelry Lab Diamond Ring Designer Stacking Adjustable Ring
Located in Jaipur, IN
This 14K yellow gold "Toi et Moi" bypass ring features two pear-cut lab diamonds positioned in an open-ended, wrap-around design. Details:- Item Code :-LRIMJOS-002 Material - 14K So...
Diamond, Gold, 14k Gold, Yellow Gold
IGI Certified Natural uncut rose cut Diamond sterling silver eternity band Ring
Located in Delhi, DL
-Diamond type- Natural rose cut, natural uncut diamond -Diamond color- white with a tint of grey -Diamond weight- 2.65ctw -Metal- 925 Sterling silver Metal color- oxidized silver...
Diamond, Sterling Silver
Set in 18K Gold, Blue Sapphires, Black Enamel & tapered Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Blue Sapphire & Black Enamel Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Blue Sapphire is 0.68 carats. The Blue Sapphir...
Diamond, Blue Sapphire, 18k Gold, Enamel
Set in 18K Gold, 9.18 carats, Zambian Emerald & Yellow Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very. gorgeous and beautiful, modern style, Emerald Engagement Ring set in 18K Gold & natural Diamonds. The weight of the Emerald is 9.18 carats. The Emerald is completely natural,...
Yellow Diamond, Emerald, 18k Gold
Set in 18K Gold, 7.28 carat Morganite, Tanzanites & Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Morganite & Tanzanites Cocktail Ring set in 18K White Gold & natural Diamonds. The weight of the Morganite is 7.28 carats. The weight of ...
Diamond, Morganite, Tanzanite, 18k Gold
Certified Columbian Emerald Ring 2.30ctw Emerald 14K Solid Yellow Gold Ring
Located in Delhi, DL
*DETAILS- -Gross weight- 1.710 gram ------------------------------------------------- - Gold Purity: 14k ( 585 ) (Hallmark) - Gold Color: Yellow -----------------------------------...
Emerald, Yellow Gold
Set in 18K white Gold, 7.10 carats Aquamarine & Yellow Diamonds Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Aquamarine Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Aquamarine is 7.10 carats. The combined Diamonds w...
Aquamarine, White Diamond, Yellow Diamond, 18k Gold, White Gold
$6,160Sale Price|20% Off
Cushion Cut Yellow Diamond Engagement Ring & Halo Diamond Setting in 18k Gold
By Artisan NYC
Located in New York, NY
"18KT:4.304g, Diamond:1.62ct, Size: US-7"
Diamond, Yellow Diamond, White Gold, 18k Gold
$12,400Sale Price|20% Off
Set in 18K white Gold, 3.86 carats, Rose Cut Diamonds Engagement Cocktail Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Art Deco style, Rose Cut Diamonds Engagement Ring set in 18K White Gold & natural Diamonds. The combined Rose Cut Diamonds weight is 3.86 carats. Other...
Diamond, White Gold
$4,480Sale Price|20% Off
Set in 18K Gold, 1.92 carat Zambia Emerald, Black Onyx & Diamond Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, Art - deco style & unisex, Emerald & Black Onyx Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Emerald is 1.92 carats. The...
Diamond, Emerald, Onyx, 18k Gold
Toi Et Moi Ring Emerald And Pear Cut, 925 Silver Two Stone Engagement Ring.
Located in Chicago, IL
Toi Et Moi Ring Emerald And Pear Cut, 925 Silver Two Stone Engagement Ring. Base Material: 925 Sterling Silver. Main Stone: Moissanite. Moi...
Silver
14k Gold Diamond Ring IGI Certified Diamond Ring Round Solitaire Diamond Ring
Located in Delhi, DL
Details are here below: Item No- PJRD1101 Metal- Yellow Gold Metal purity- 14K Hallmark Hallmarked- Yes Diamond weight- .32ct Diamond color-G- H Diamond Clarity- I1 Diamond Cut- Ex...
Diamond, 14k Gold
Set in 18K Gold, Guild Certified Conch Pearl, Emeralds & Diamond Engagement Ring
By JEWEL HUB
Located in Hong Kong, HK
A very gorgeous and beautiful, modern style, Conch Pearl & Emeralds Engagement Ring set in 18K White Gold & natural Diamonds. The weight of the Conch Pearl is 8.26 carats. The Conch ...
Diamond, Emerald, Pearl, 18k Gold
There are many ways to showcase a diamond, from traditional prongs to a smooth, streamlined bezel. Here’s everything you need to consider.
If diamonds don’t seem right, what about a magnificent sapphire, ruby or emerald?
Accounting for just 1 percent of all diamonds, these marvels of nature are exceedingly rare and gorgeously complex.
Learn about these antique jewelry styles, then choose a design that speaks to you.
Alon Ruschin, of Vivid Diamonds & Jewelry, channels his passion for gems into helping clients find just the right ring.
If a classic solitaire isn't for you, explore these alluring alternatives.
Thinking of going bespoke but not sure what it entails? We ask the experts what you need to know.
Ready to rock? Some of our favorite jewelry designers and dealers share indispensable advice for choosing that most important ring.