S

Sapphire watch crystal - A watch crystal made from synthetic sapphires. At 9.5 on the Moh's scale, a sapphire crystal can only be scratched by diamonds.

Saturation - A word used to describe the purity of color in gemstones.

Semi-translucent - One step up from opaque in judging the amount of light that passes through "transparent" gemstones.

Semi-transparent - One step down from transparent in judging the amount of light that passes through "transparent" gemstones.

Shank - The part of a ring that encircles the finger.

Shape - Rounds, pears, ovals, etc., and any other shape of a gemstone's cut.

Side stone - The stone or stones that accent a center stone in a jewelry setting.

Single cut - Small diamonds are given a simple cut of 17 or 18 facets.

South-sea pearls - Typically white, south-sea pearls are larger than Akoya's, beginning at 10mm and averaging 11 to 14mm.

Sparkle - The fire and brilliance created by light passing through a diamond.

Specific gravity - The ratio of a gem's density to the density of water. A measurement to determine size against carat weight.

Star rubies and sapphires - A cabochon cut stone with an inclusion that creates a star effect.

Step cut - Emerald cuts, or baguettes, where the facets are four sided and run parallel to the girdle.

Surface markings - The degree to which a pearl is graded for surface perfection.

Surface diffusion - A relatively new color treatment for grayish blue sapphires that is gaining acceptance. It has been controversial because although the treatment is permanent, it is only skin deep and can be scratched or polished off.

Symmetrical - An off round pearl that has the same dimensions on both ends.

Symmetry - The uniformity of a gemstones cut is described as its symmetry. Graded from poor to excellent, only those ranked good to excellent should be considered.

Synthetic - Any gemstone grown in a lab. They are "real" gemstones, but they are not "real" diamonds, rubies, etc.

T

Table - The largest facet on a gemstone. The table is on top of the crown and allows refracted light to escape, creating brilliance.

Table size - Most jewelers agree the table should be between 53% and 67% of the girdle diameter. A table percentage too large or small greatly effects sparkle.

Table percentage - The diameter of the gemstone divided by the size of the table.

Tahitian pearls - Large Polynesian pearls known for their natural black luster.

Teardrop - Another word for pear shaped pearls.

Tone - Along with hue and purity, tone helps determine the color of gemstones.

Total weight - A term to watch out for in jewelry shopping. Always determine the price-per-carat and find out the weight of individual stones.

Trilliant - A brilliant cut triangle gemstone.

U

Ultrasonic - A cleaning machine for gemstones and jewelry that blasts dirt away with ultrasonic waves. They are commonly available in hardware stores, but cannot be used on all types of gemstones. Be sure to consult a professional jeweler before cleaning any jewelry.

Uniformity - The grading system for defining how well pearls match on a strand. They can be excellent, good or fair.