Table Facet

The largest facet of the diamond, a table is the flat surface on the top of the stone, resembling a ‘table’.


A name coined by Tiffany & Co. for one of the most beautiful stones found in recent history. Tanzanite is a violetish blue stone that was discovered in 1967 when a Masai tribesman discovered the crystal in Northern Tanzania, Eastern Africa. Read more

Tension Set

A setting whereby a gemstone is held in place by pressure rather than by other types of mounting such as prongs or bezel.

Tiffany & Co.

An American jewellery house known for producing top quality jewellery and silverware, founded in 1837 in New York. Tiffany & Co is known for its superlative craftsmanship and pioneering work in the gemology arena.

Tigers Eye

A brown variety of quartz, normally cut as a cabochon to display chatoyancy.


A gemstone, which, in its purest form is colourless, but is normally known for being blue or yellow.  Topaz derives from the name of an island in the red sea ‘topazos’. In Sanskrit topaz also means ‘fire’. Read more


The word tourmaline derives from the Sinhalese word ‘thuramali’  which means simply gemstones or pebbles.  Tourmaline is known for the dazzling array of vibrant colours in which it is available. Read more

Trade Terms

Terms used in the jewellery industry to describe particular gemstone colours or link gemstones with specific geological areas – such as ‘Burmese’ or ‘Pigeon’s Blood’.

Transitional Cut

1870s – 1940s. This is the transition between the old European and the modern brilliant cuts. The angles of these stones are more similar to the modern brilliant to other antique cuts. For example, the table facet size is increased, and culets are nearly nonexistent or ‘somewhat large’ but could not be described as ‘large’ or ‘open’.


First mined 5,000 years ago by Tibetans and Egyptians, turquoise’s colour can range from dull greys, to yellows, grass greens to bright sky blues. The most prized colour, a bright robins egg blue, comes from the Nishapur district of Iran. This is sometimes said to be ‘Persian Blue’. Turquoise has long been a symbol of wealth as well as being associated to meanings of purity and healing. Read more