Rainbow Moonstone
This layered gemstone has a beautiful blue hue that is formed from a combination of orthoclase and albite arranged in layers. 
Rainbow Pyrite
Rainbow Pyrite comes in the form of drowsiness miniature pyrite crystals coat a matrix.
Rhodochrosite
Rhodochrosite is both light and dark, which is shown in its zigzag banding.
Rhodolite Garnet
Rhodolite Garnet is a mixture of pyrope and almandite. Rhodolite is lighter than other red garnets.
Scapolite
Scapolite comes in a vibrant yellow, orange, pink or violet and is sought after by many admirers.
Seraphinite
Seraphinite is a clinochlore. Mica inclusions give it its silvery and feathery shimmer that highlight its green hues.
Smoky Quartz
Smoky quartz is tribal and earthly looking. It is extremely popular.
Sodalite
Sodalite is named for its sodium content. It is usually blue, with a violet tint, and most of the time contains white veins of calcite.
Spessartite Garnet
Spessartite garnets display a bright, orange red. The best specimens come from Namibia.
Sphalerite
Sphalerite is a rare collector's gem that resembles fire. Its dispersion rate is higher than diamond.
Sphene
Sphene is a high luster gemstone that is brilliant yellowish-green, green or brown. It has a exceptional cut.
Star Sunstone
Sunstone is a gemstone that has green, blue, or red glitter that is formed from platelets of hematite.
Rhodonite
Rhodonite is composed of manganese iron magnesium calcium silicate and has pinky red hues, lined with black throughout.
Rose Quartz
Rose quartz is a soft pink due to the tiny traces of titanium. Rose quartz crystals tend to be cloudy which heightens the color.
Rubellite Tourmaline
Rubellite is vivid pink to red tourmaline. It is the most sought after tourmaline.
Ruby
Ruby contains corundum, and is very valuable. This is because of it's rich color and hardness. 
Sillimanite Cat's Eye
Sillimanite is an aluminum silicate, that share the same composition as andalusite and kyanite. 
Smithsonite
Smithsonite is one of two zinc-containing minerals that were named after its discoverer, Smithson. Smithsonite is a zinc silicate that was named in his honor.
Spinel
Spinel is a hard gemstone that has good clarity. Color is a hue of purple. 
Spodumene
Spodumene occurs in white, gray, pink, lilac and green. It is a relatively new gemstone, only recently been discovered.
Star Diopside
Diopside is a vivid green color, but the black diopside exhibits asterism or the star effect is also favored by many.
Star Garnet
Star garnet is a garnet, found only in Idaho and in India. Aligned inclusions of rutile give it is four-ray star.
Sunstone
Sunstone contains red hematite which gives it a spangled appearance.
Strawberry Quartz
Hematite or goethite and even lepidocrosite is found in strawberry quartz.
Ruby Zoisite
Ruby-Zoisite is often used for carvings. Ruby and Zoisite crystals are often found in a single specimen. 
Rutile Quartz
Rutile Quartz is clear in color or is a smoky quartz with inclusions of rutile crystals.
Rutile Topaz
Rutile Topaz is colorless with inclusions that look like rutile crystals. It is actually limonite staining in thin lines within the topaz.
Sapphire
Sapphire, with its lovely shade of blue, and excellent hardness. It is one of the traditional gemstones, second only to diamond.
Serpentine
Serpentine is used as a decorative stone or carvings due. It is composed of green magnesium silicate aggregate.
Snowflake Obsidian
Obsidian is volcanic glass. The inclusion of white crystals of cristobalite in some stones produce a blotchy pattern, known in as snowflake obsidian.
Star Moonstone
Moonstone gets its color from the minerals orthoclause and albite which are layered within the gemstone. Cat's eye or the star effect is known as a star moonstone.
Star Rose Quartz
Rose quartz is formed from titanium impurities. Rose quartz rarely has the star effect.
Star Ruby
Star Ruby is a ruby gemstone that shows a six-rayed star when the sun shimmers over the surface of it and it is moved.
Star Sapphire
Star Sapphire is a gemstone that has inclusions called asterism.
Sugilite
Sugilite is an extremely rare gemstone that was discovered in 1944.
