Skip to main content

Antique Ring Size 5

to
97
1,584
547
1,499
1,499
614
597
383
252
250
128
88
86
42
39
34
27
24
14
13
11
10
9
9
8
4
4
3
3
2
2
2
2
2
2
1
1
1
1
1
1
1
20
3
3
3
3
Sort By
Victorian Old Mine Cut Diamond and 18 Carat Gold Cluster Ring
Located in Chipping Campden, GB
Size: K or 5 1/4 Cluster Diameter: 11mm Height Off Finger: 6mm Weight: 2.8g
Category

1880s British Victorian Antique Ring Size 5

Materials

Diamond, Gold

Antique Victorian 18K Yellow Gold and Silver 0.6ctw Diamond Cluster Ring
Located in Staines-Upon-Thames, GB
weight, estimated: 0.23ct Total diamond weight, estimated: 0.6ct Gross weight: 5.6g Ring size: UK – N.5
Category

Late 19th Century Victorian Antique Ring Size 5

Materials

Diamond, 18k Gold, Yellow Gold, Silver

Art Deco Sapphire and Diamond 18 Carat Gold Cluster Ring
Located in Chipping Campden, GB
reads 'G.Y.M - M.K.M 25.12.24'. Modelled in 18carat gold. Ring Size: K 1/2 or 5 1/2 Cluster
Category

1920s British Art Deco Antique Ring Size 5

Materials

Diamond, Sapphire, Gold

Antique Victorian Opal Diamond Ring Enamel 18k Yellow Gold 5.5 Cocktail Jewelry
Located in Torrance, CA
opals are in good condition and free of cracks or chips. Size & Measurements: The ring is a size 5 1/2
Category

Late 19th Century Unknown Victorian Antique Ring Size 5

Materials

Diamond, White Diamond, Opal, Gold, 18k Gold, Yellow Gold, Enamel

Antique Victorian 18K Yellow Gold 1.58tgw Sapphire, Diamond and Ruby Ring
Located in Staines-Upon-Thames, GB
: 0.54ctw Total gem weight, estimated: 1.58ctw Gross weight: 8.61g Ring size: UK – J.5 US - 5 EU
Category

1890s Victorian Antique Ring Size 5

Materials

Diamond, Ruby, Sapphire, 18k Gold, Yellow Gold

Antique Victorian Ring Opal Rose Cut Diamond Cluster 10k Yellow Gold Pinky Halo
Located in Torrance, CA
loupe). Size & Measurements: The ring is a size 5 1/2 (sizable). The mount measures 9.5mm diameter
Category

Late 19th Century American Victorian Antique Ring Size 5

Materials

Diamond, White Diamond, Opal, Gold, 10k Gold, Yellow Gold

Antique Edwardian 18K Yellow Gold Old Cut Diamond Belcher Solitaire Ring
Located in Staines-Upon-Thames, GB
: 0.19ctw Gross weight: 3.1g Ring size: UK – M.5 US – 6.5 EU – 53 mm Hallmarks: 18 (18 karat gold
Category

1910s Edwardian Antique Ring Size 5

Materials

Diamond, 18k Gold, Yellow Gold

Antique Edwardian 0.55ct Diamond Engagement Ring Vintage Platinum Bridal Jewelry
Located in Torrance, CA
& Measurements: The ring is a size 5 1/2 (sizable). The mount measures 10mm wide (0.39 inches) rising 6mm from
Category

Early 20th Century Unknown Edwardian Antique Ring Size 5

Materials

Diamond, White Diamond, Platinum

Antique Victorian 18K Gold and Silver 0.85ctw Old Cut Diamond Double Row Ring
Located in Staines-Upon-Thames, GB
: 3.5g Ring size, approximately: UK – O.5 US – 7 ½ EU – 55.5 mm Hallmarks: stamped ‘18’, tests as 18
Category

Late 19th Century British Victorian Antique Ring Size 5

Materials

Diamond, 18k Gold, Yellow Gold, Silver

Edwardian Turquoise and Diamond Point Five-Stone 15 Carat Gold Ring
Located in Chipping Campden, GB
points that sit between the oval turquoise stone cabochons. Ring Size: J 1/2 or 5 Weight: 6.5g
Category

Early 1900s British Edwardian Antique Ring Size 5

Materials

Diamond, Turquoise, 18k Gold, Gold

Art Deco Emerald and Diamond 14 Carat White Gold Solitaire Ring
Located in Chipping Campden, GB
totalling 10pts per shoulder. The ring is modelled out of 14carat white gold. Ring Size: L or 5 3/4
Category

1920s British Art Deco Antique Ring Size 5

Materials

Diamond, Emerald, White Gold

Antique Edwardian 14K Gold Platinum 0.81ctw Old Cut Diamond and Pearl Ring
Located in Staines-Upon-Thames, GB
, estimated: 0.81ctw Ring size: UK – L.5 US – 6 EU – 52 mm Gross weight: 3.7g Hallmarks: none, tests as
Category

Early 20th Century British Belle Époque Antique Ring Size 5

Materials

Pearl, Diamond, Platinum, Yellow Gold, 14k Gold, 10k Gold

Art Deco 1920s Platinum 18K Yellow Gold Emerald Diamond Panel Ring
Located in Staines-Upon-Thames, GB
diamond weight, estimated: 0.2ctw Gross weight: 2.9g Ring size: UK – M.5 US – 6.5 EU – 53 mm
Category

1920s Art Deco Antique Ring Size 5

Materials

Diamond, Emerald, 18k Gold, Yellow Gold, Platinum

Vintage Art Deco 1.70ct Diamond Ring Cluster 14k Gold Halo Engagement Bridal
Located in Torrance, CA
at L-M and SI1-I2 clarity). Size & Measurements: The ring is a size 5 1/2 (sizable). The mount
Category

Early 20th Century American Art Deco Antique Ring Size 5

Materials

Diamond, White Diamond, Gold, 14k Gold, White Gold

Victorian Snake Ring Garnet Eyes Three Dimensional Gold Antique Circa 1860
Located in New York, NY
ring sits 6mm above the finger. The ring is currently a size 5 US (J 1/2 UK) and can be easily resized
Category

19th Century Unknown Victorian Antique Ring Size 5

Materials

Garnet, Gold, 10k Gold, Yellow Gold

Art Deco 1920s Platinum 0.78ctw Diamond Solitaire Ring with Diamond Shoulders
Located in Staines-Upon-Thames, GB
size: UK – N.5 US – 7 EU – 54.25 mm Hallmarks: stamped “PLAT” (platinum), circa 1920
Category

Early 20th Century Art Deco Antique Ring Size 5

Materials

Diamond, Platinum

Art Deco GIA Cert 1.02 Carat Diamond Platinum Engagement Ring
Located in New York, NY
baguette and round cut diamond accents. The ring is size 5, and can be resized. Inventory #70795WBAB
Category

Early 20th Century Antique Ring Size 5

Materials

Diamond, Platinum

1.36 Carat Old Mine Brilliant Cut Diamond Platinum Engagement Ring
Located in New York, NY
accentuated by dazzling baguette cut diamond accents. The ring is size 5 1/4, and can be resized. Inventory
Category

Early 20th Century Antique Ring Size 5

Materials

Diamond, Platinum

Antique Edwardian Sapphire Diamond Ring Vintage Platinum Long Plaque Jewelry
Located in Torrance, CA
condition and free of cracks or chips. Size & Measurements: The ring is a size 5 1/2 (sizable). The mount
Category

Early 20th Century Unknown Edwardian Antique Ring Size 5

Materials

Diamond, White Diamond, Sapphire, Blue Sapphire, Platinum

Antique Signed Art Deco 18k Gold Amethyst Filigree Ring with Lovebirds
Located in Philadelphia, PA
to the interior of the ring. Ring Size: ca. 5 3/4 Maker: Baskin Bros. of New York, New York
Category

Early 20th Century American Art Deco Antique Ring Size 5

Materials

Amethyst, 18k Gold, White Gold, Yellow Gold

Art Deco 1930s 18K White and Yellow Gold Ruby and Diamond Geometric Ring
Located in Staines-Upon-Thames, GB
wide at the back. Ruby weight, estimated: 0.9ct Gross weight: 1.5g Ring size: UK – N.5 US – 7 EU
Category

1920s British Art Deco Antique Ring Size 5

Materials

Diamond, Ruby, 18k Gold, White Gold, Yellow Gold

Antique Edwardian 14K Yellow Gold, Blue Topaz, Seed Pearl Signet Style Ring
Located in Philadelphia, PA
: Marked 14k for gold fineness. Professionally tests at 14k. Ring Size: ca. 5 1/2 Gemstone Measurements
Category

Early 20th Century Unknown Edwardian Antique Ring Size 5

Materials

Pearl, Topaz, Blue Topaz, 14k Gold, Yellow Gold

Vintage Art Deco Double Aquamarine Ring Filigree 14k Gold Elongated Hexagon
Located in Torrance, CA
& Measurements: The ring is a size 5 3/4 (sizable). The mount measures 18mm in length (0.70 inches) and 6mm wide
Category

Early 20th Century American Art Deco Antique Ring Size 5

Materials

Aquamarine, Gold, 14k Gold, White Gold

Art Deco 18 Carat Gold and Platinum Sapphire and Diamond Panel Ring
Located in Chipping Campden, GB
carat white gold. Sapphire 50pts, diamond total approx 60pts. Ring Size: L or 5 3/4 Panel Dimensions
Category

1910s Unknown Art Deco Antique Ring Size 5

Materials

Diamond, Sapphire, Gold, Platinum

Antique Georgian 1771 22K Yellow Gold Black Enamel Amethyst Hairwork Urn Ring
Located in Staines-Upon-Thames, GB
at the back. The ring rises 4.5mm off the finger. Ring size: UK – N.5 US – 7 EU – 54.5 mm Gross
Category

Late 18th Century British Georgian Antique Ring Size 5

Materials

Amethyst, 18k Gold, 22k Gold, Yellow Gold, Enamel

Art Deco Diamond Emerald and Quartz Plaque Ring 18K White Gold
Located in beverly hills, CA
comfortably on the finger with a low profile. The ring is a size 5 (sizable). Measurement: 8.8 x 18 mm
Category

Early 20th Century Art Deco Antique Ring Size 5

Materials

Diamond, Emerald, Quartz, White Gold

Antique Victorian Emerald and Solitaire Diamond Ring in Platinum Estate
Located in New York, NY
Antique Victorian Emerald & Solitaire Diamond Ring In Platinum Estate Size 5 Old Treasure
Category

Early 20th Century Antique Ring Size 5

Materials

Diamond, Emerald, Platinum

Antique Victorian 15K Gold Rhodolite Garnet and Pearl Ring with Engraved Band
Located in Staines-Upon-Thames, GB
hand. Total garnet weight, estimated: 0.54ctw Pearl size, each: 3mm Gross weight: 1.8g Ring size: UK
Category

1870s British Victorian Antique Ring Size 5

Materials

Garnet, Pearl, Rhodolite, 15k Gold

Vintage Belais Art Deco Opal Ring 14k White Gold Filigree Fine Jewelry
By Belais
Located in Torrance, CA
ring is a size 5 (sizable). The mount measures 18mm in length (0.70 inches) and 10mm wide (0.39 inches
Category

Early 20th Century American Art Deco Antique Ring Size 5

Materials

Opal, Gold, 14k Gold, White Gold

Art Deco 1.25 CTW Old European Cut Diamond Platinum Engagement Ring
Located in Towson, MD
likely to catch on things during daily wear. The ring is a US finger size 5 and is sizeable, though this
Category

1920s American Art Deco Antique Ring Size 5

Materials

Diamond, Platinum

Antique Victorian Gold Nugget Conversion Ring 14k Vintage Mined Jewelry Estate
Located in Torrance, CA
& Measurements: The ring is a size 5 1/2 (sizable). The mount measures 15mm in length (0.59 inches) and 13mm wide
Category

Late 19th Century Unknown Victorian Antique Ring Size 5

Materials

Gold, 14k Gold, 22k Gold, 24k Gold

Art Deco 14K Yellow Gold Platinum 0.6ctw Transitional Cut Diamond Trilogy Ring
Located in Staines-Upon-Thames, GB
at the back. Total diamond weight, estimated: 0.6ctw Gross weight: 2.75g Ring size: UK – N.5 US
Category

1920s Art Deco Antique Ring Size 5

Materials

Diamond, 14k Gold, Yellow Gold, Platinum

Antique Victorian Talon Claw Ring Moonstone Conversion 14k Rose Gold Sz 5.5
Located in Torrance, CA
with a 5.5mm luminous moonstone orb. Size & Measurements: The ring is a size 5 1/2 (sizable). The
Category

Late 19th Century Unknown Victorian Antique Ring Size 5

Materials

Moonstone, Gold, 14k Gold, Rose Gold

Edwardian 7 Diamond Cluster Ring with Scalloped Setting in 14k White Gold
Located in beverly hills, CA
finger. The ring comes in size 5 but can be resized to fit your finger perfectly. This beautiful diamond
Category

Early 19th Century Edwardian Antique Ring Size 5

Materials

Diamond, 14k Gold, White Gold

Vintage Art Deco Ruby Eternity Ring Sz 5.5 Anniversary Band Stacking Jewelry
Located in Torrance, CA
10x loupe). Size & Measurements: The ring is a size 5 1/2 (not sizable). The band measures 2.5mm wide
Category

Early 20th Century Unknown Art Deco Antique Ring Size 5

Materials

Ruby, Platinum

Art Deco Diamond and 18 Carat Yellow and White Gold Eternity Ring
Located in Chipping Campden, GB
gold. Ring Size: K 1/2 or 5 1/2 Band Width: 5mm Weight: 4g
Category

1910s British Art Deco Antique Ring Size 5

Materials

Diamond, Gold, 18k Gold, White Gold

J.J. De Gault Bacchus Gouache Trompe L oeil Ring
Located in Amsterdam, NL
. It is a miniature trompe l’oeil! ring size: 16,25 mm 5 1/2 US.
Category

Late 18th Century French Antique Ring Size 5

Materials

18k Gold

Antique Art Deco 10k Rose Yellow Gold Buckle Ring with a Moonstone Cabochon
Located in Philadelphia, PA
: Unmarked Fineness: Unmarked for gold fineness. Professionally tests at 10k Ring Size: ca. 5 Gemstone
Category

Early 20th Century American Art Deco Antique Ring Size 5

Materials

Moonstone, 10k Gold, Yellow Gold

Antique Victorian 18K Gold 0.61ct Old Mine Cut Diamond Belcher Solitaire Ring
Located in Staines-Upon-Thames, GB
, estimated: 0.61ct Gross weight: 2.9g Ring size: UK – N.5 US – 7 EU – 54.25 mm Hallmarks: none, tests as
Category

1880s Victorian Antique Ring Size 5

Materials

Diamond, 18k Gold, Yellow Gold

Collins 18k White Gold Ring with 7 ct Star Ruby .12 ctw Natural Diamonds
Located in Greeneville, TN
Stones: .12 ctw Natural Round Diamonds (SI-I1 clarity) Ring Size: US 5 Finish: High-polish, luxury
Category

15th Century and Earlier American Modern Antique Ring Size 5

Materials

Diamond, Ruby, Star Ruby, White Gold

Art Deco 1920s Platinum 1.27ctw Old European Cut Diamond Rectangular Panel Ring
Located in Staines-Upon-Thames, GB
: 1.27ctw Gross weight: 3.7g Ring size: UK – I.5 US – 4.5 EU – 48.25 mm Hallmarks: remnants of a ‘PLAT
Category

Early 20th Century Art Deco Antique Ring Size 5

Materials

Diamond, Platinum

Antique circa 1900s Diopside, Opal White Topaz Fancy Cocktail Ring in Silver
Located in Bangkok, TH
, evoking the splendor and romance of a bygone era with every glance. The ring size of the ring is US SIze
Category

Early 1900s Gilded Age Antique Ring Size 5

Materials

Opal, Topaz, Silver

Antique Art Deco Fillagree Diamond Ring Set in 14 Karat White Gold
Located in Los Gatos, CA
cut Diamonds with an estimated t.w. of 1/2 carat. This ring is a size 5 1/4 it measures 19.9 mm x
Category

19th Century Art Deco Antique Ring Size 5

Materials

14k Gold

Antique Victorian Emerald Diamond Ring 18k Yellow Gold Vintage Fine Jewelry 5.5
Located in Torrance, CA
ring is a size 5 1/2 (not sizable). The mount measures 14mm in length (0.55 inches) and 10mm wide (0.39
Category

Late 19th Century Unknown Victorian Antique Ring Size 5

Materials

Diamond, White Diamond, Emerald, Gold, 18k Gold, Rose Gold

Stunning 1.28 Carat Old Mine Cushion Cut Diamond Platinum Engagement Ring
Located in New York, NY
and diamond accents. The ring is currently size 5 1/4, and can be resized. Inventory #E91637NPSS
Category

Early 20th Century Art Deco Antique Ring Size 5

Materials

Diamond, Sapphire, Platinum

Vintage Men s 4.20 Carat Tourmaline and Single Cut Diamonds Royal Signet Ring
Located in Miami, FL
. The diamonds are antique single cut diamonds. The ring is a size 5. The ring is incredibly attractive
Category

1920s Art Deco Antique Ring Size 5

Materials

Diamond, Tourmaline, 14k Gold, Yellow Gold

Vintage Art Deco 1ct Diamond Engagement Ring Platinum Estate Fine Bridal Jewelry
Located in Torrance, CA
color and SI1 clarity). Size & Measurements: The ring is a size 5 1/4 (sizable). The mount
Category

Early 20th Century American Art Deco Antique Ring Size 5

Materials

Diamond, White Diamond, Platinum

Art Deco Platinum and 14K White Gold 0.85ctw Old Cut Diamond Trilogy Panel Ring
Located in Staines-Upon-Thames, GB
weight, estimated: 0.47ct Total diamond weight, estimated: 0.85ctw Ring size: UK – N.5 US – 7 EU
Category

1920s British Art Deco Antique Ring Size 5

Materials

Diamond, 14k Gold, White Gold, Platinum

Art Deco 14k Diamond Three Stone Ring
Located in Narberth, PA
paired with other white gold rings! Measurements: The ring is a finger size 5, but could be slightly
Category

1920s Art Deco Antique Ring Size 5

Materials

Diamond, Gold, 14k Gold, White Gold

Art Deco 1920s 18K White Gold 1.54ctw Old European Cut Diamond Panel Ring
Located in Staines-Upon-Thames, GB
diamond weight, estimated: 1.54ctw Gross weight: 4.3g Ring size: UK – N.5 US – 7 EU – 54.25 mm
Category

Early 20th Century Art Deco Antique Ring Size 5

Materials

Diamond, 18k Gold, White Gold

Antique Victorian Opal Diamond Ring 14k Yellow Gold Sz 5.75 Fine Vintage Jewelry
Located in Torrance, CA
). The opal is in very good condition and free of cracks or chips. Size & Measurements: The ring is a
Category

Late 19th Century Unknown Victorian Antique Ring Size 5

Materials

Diamond, White Diamond, Opal, 14k Gold, Yellow Gold

Victorian Turquoise and Rose Cut Diamond 9 Carat Gold Cluster Locket Back Ring
Located in Chipping Campden, GB
the centre. Ring Size: L or 5 3/4 Cluster Diamater: 10mm Weight: 2.9g
Category

1880s British Victorian Antique Ring Size 5

Materials

Turquoise, Diamond, Gold

Antique Deco Diamond Filigree Ring Vintage 14 Karat Gold Estate Fine Jewelry
Located in Torrance, CA
I1 clarity. Size & Measurements: The ring is a size 5 (sizable). The mount measures 23mm in length
Category

Early 20th Century Unknown Art Deco Antique Ring Size 5

Materials

White Diamond, 14k Gold, White Gold

Gold ring with Roman Pink Agate Cameo depicting Two Putti 3rd-4th Century A.D.
Located in Firenze, IT
Period: 3rd – 4th century Measurements: 20 x 11 mm Ring size: 7 Weight: 5, 80 gr The ring
Category

15th Century and Earlier Italian Classical Roman Antique Ring Size 5

Materials

Agate, Gold, 22k Gold, Yellow Gold

Victorian 14 Karat Yellow Gold and Undyed Red Coral Cameo Fashion Ring
Located in Lexington, KY
features a vintage mark on the inside, adding to the allure of this piece! The ring is currently a size 5
Category

1890s Victorian Antique Ring Size 5

Materials

Coral, Gold, 14k Gold, Yellow Gold

Victorian 18 Karat Yellow Gold Ruby and Diamond Five-Stone Half Hoop Ring
Located in Chipping Campden, GB
Victorian gallery. A truly stunning antique ring that would make a fabulous family heirloom. Ring Size : K
Category

Late 19th Century Victorian Antique Ring Size 5

Materials

Diamond, White Diamond, Ruby, Gold, 18k Gold, Yellow Gold

Antique Deco 1 Carat Diamond Engagement Ring 14 Karat Gold Filigree Fine Vintage
Located in Torrance, CA
estimated 1 carat Old Mine cut (estimated at I-J color and I1 clarity). Size & Measurements: The ring is a
Category

Early 20th Century Unknown Art Deco Antique Ring Size 5

Materials

Diamond, 14k Gold, White Gold

  • 1
  • ...
Get Updated with New Arrivals
Save "Antique Ring Size 5", and we’ll notify you when there are new listings in this category.

Antique Ring Size 5 For Sale on 1stDibs

On 1stDibs, you can find the most appropriate antique ring size 5 for your needs in our varied inventory. Every item for sale was constructed with extraordinary care, often using Gold, 18k Gold and Yellow Gold. You’re likely to find the perfect antique ring size 5 among the distinctive items we have available, which includes versions made as long ago as the 18th Century as well as those produced as recently as the 20th Century. Creating an antique ring size 5 has been a part of the legacy of many jewelers, but those produced by Cartier, Georg Jensen and Tara Shaw are consistently popular. An antique ring size 5 can make for a versatile accessory, but a selection from our variety of 49 Diamond versions can add an especially stylish touch. See these pages for an old european cut iteration of this accessory, while there are also round cut cut and oval cut cut versions available here, too. There aren’t many items for men if you’re seeking an antique ring size 5, as most of the options available are for women and unisex.

How Much is a Antique Ring Size 5?

Prices for an antique ring size 5 can differ depending upon size, time period and other attributes — at 1stDibs, these accessories begin at $33 and can go as high as $15,500, while this accessory, on average, fetches $850.

Finding the Right Rings for You

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 ringsvintage 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.