Basically: Bands

Textured Band

14 k white gold

It has been hammered to have the texture it has.

http://wedding-band-ring.com/Merchant2/graphics/00000015/WED-PAC.jpg

Smooth Band

Platinum wedding band

http://www.silvabac.com/images/proimgs/634989863864322848.jpg

These, usually plain, are rings that were traditionally used for giving brides and sometimes grooms for weddings. Presently they maybe worn as accessories.

http://www.thefreedictionary.com/wedding+band

Colourful and Simple: Dome Ring

Garden Flower Domed Ring

Designed by Coach
They have a collection of domed rings,unfortunately, finding information on this one was difficult. However I'm intrigued by the use of coloures on this piece.

http://cdnc.lystit.com/photos/2013/01/16/coach-goldmulticolor-garden-flower-domed-ring-product-1-6074395-756920678_large_flex.jpeg

Gold Dome Ring

9 ct gold

http://gerrim.com/portal/images/stories/PRODUCT_IMAGES/dsc_6126.jpg

http://gerrim.com/portal/content/view/15/106/

: A piece of jewellery with a convex shape, thicker in the centre and tapering at the edges.
Door Knocker Earring: An earring with a hinged bottom that hangs below the earlobe.

http://en.mimi.hu/jewelry/domed.html

Animal Heads: Costume Rings

Leopard Head Ring

Alloy, Silver Plating
Cubic Zirconia, Leopard Head design

http://www.followbest.com/product/24k-gold-plated-turquoise-eagle-head-ring-p1528.html

Eagle Head Ring

24 k gold plated

22 x 15 mm Turquoise

Cubic Zirconia 

http://www.followbest.com/product/24k-gold-plated-turquoise-eagle-head-ring-p1528.html 

Costume rings are made from inexpensive metals and imitations of precious stones, usually. the metals are usually alloyed. but regardless of this, costume rings or jewellery are flashy and fashion set.

http://www.wisegeek.com/what-is-costume-jewelry.htm

Pronouncing Fidelity: Engagement Rings

Black Diamond Engagement Ring
14 k Black Gold
1.70 ct Black Round Diamond 

http://www.squidoo.com/black-gold-rings

Butterfly and Vine Engagement and Wedding Ring Set

18 k yellow gold

15 x 0.010 ct diamonds

18 k yellow gold

22 x 0.010 ct diamonds

1.0 carat (6.5 mm diam) white sapphire

Sandblast on gold metal detail

http://www.etsy.com/listing/104181848/nature-inspired-18k-yellow-gold-10-ct 

Engagement rings are the rings that are worn before the symbolic marriage ceremony. They are usually more extravagant compared to the marriage rings, even though they may match.

http://www.wisegeek.org/what-is-the-difference-between-engagement-rings-and-wedding-rings.htm

Natural Ring Sets

The Acadia Wedding Ring Set

14 k white gold.

0.25 ct brilliant-cut diamond.

E-F colour and VS-1 clarity.

http://www.etsy.com/listing/112477184/the-acadia-wedding-ring-set-gold-and 

Delicate Leaf Wedding Ring Set

14 k yellow gold, also comes in white and rose gold.
4 mm white sapphire.

http://library.hrmtc.com/2013/02/19/leaf-and-twig-design-ring-sets/ 

Ring sets, usually known for engagement and wedding rings, are rings that are more than one but worn as a single piece or ring. The engagement ring is usually first then the wedding ring fits in with it.

http://library.hrmtc.com/2013/02/19/leaf-and-twig-design-ring-sets/

Solitare: Antique and Modern

Vintage Solitaire Engagement Ring

Tension set.

18 k yellow gold.

0.37 ct princess-cut diamond.

 http://www.rubylane.com/item/1030574-R2273/Vintage-solitaire-0-37-carat 

Antique Victorian Diamond Solitaire Ring


18 k Gold.
Black Enamel.
The 0.55+ ct cushion-cut diamond.

http://www.rubylane.com/item/518197-RGC10410V/Antique-Victorian-Diamond-Solitaire-Ring 

Solitaire rings are set with a single gemstone as a centerpiece. Usually it's a large gemstone.

http://www.angara.com/jewelry-guide/sapphire-rings-buying-guide.html

Classic Cluster Rings

Art Nouveau Antique Russian Cluster Ring

14 K yellow gold ring.

Approximately 0.80 carat diamonds.

The shoulders are decorated with cast Art Nouveau floral designs. 

http://www.rubylane.com/item/750954-1000075/Art-Nouveau-Antique-Russian-Diamond 

Classic Edwardian Cluster Ring

18 K split shank at the shoulders.Diamonds are approximately 1/4 carat.The sapphire is approximately 1/3 carat.

http://www.rubylane.com/item/197051-7274/Classic-Edwardian-Cluster-Ring-Diamond 

Cluster rings are rings with a group of stones in a setting, called cluster setting, forming the focal point of the ring. 

http://www.angara.com/jewelry-guide/sapphire-rings-buying-guide.html

Jewellery's ancient Child: Signet Ring

Past Masters ring
From the series of Masonic signet rings By Adone T. Pozzobon
18k Gold

http://www.engravingarts.com/pgGal5_PM-Masonic1.html

Napoleaon's signet ring
For the Commander of his Honor Gaurd, Hans de Bruyere of Nimegue.
10.5 ct of diamonds
Gold

http://www.napoleonexhibit.com/item.php?id=69 

A signet ring or signature ring is a ring that has, in modern times, been characterised by personal engravements to create the seal/signature. Otherwise, it was originally used by authoritative figures (Egyptian Kings, popes, politicians etc.) to seal important documents. The seal served as prove for authenticity of document i.e. there was one owner of seal and if tempered with seal cannot be forged. The seal/signature is traditionally the top of the ring. It can be metal, gemstone or semiprecious materials.

 https://en.wikipedia.org/wiki/Seal_(emblem) 

http://www.wisegeek.org/what-are-signet-rings.htm