Diamonds of a beauty and calibre suitable to be used in jewellery. Only approximately 20% of mined diamonds are of gem quality – 80% are in fact industrial grade diamonds.
Gem Quality
Fracture Filling
Treatment to enhance the apparent clarity of a diamond, whereby a glass-like resin is injected into feathers or fractures that reach the surface of the diamond. Feathers are visible when light reflects off of them; by filling them with a resin, light is able to travel through the feather, making it less visible. The resin causes what is known as a flash effect in the treated diamond. Fracture filling is not a stable diamond treatment and is easily altered with heat; click here to learn more.
Fracture
Fluorescence
Natural characteristic which causes many diamonds to glow under ultra violet light (UV), which is abundant in natural daylight and some artificial lighting. Fluorescence is caused by sub-microscopic structures within the diamond. Diamonds can have various colours of fluorescence, with blue being the most common.
Four C’s
Four fundamental criteria on which the quality and value of a diamond are judged: cut, colour, clarity, and carat weight. Two additional factors, transparency and the confidence in a diamond grading certificate are also important value factors. Click here to learn more about the C’s of diamond grading.
Flawless
Refers to the clarity of a diamond with no inclusions or blemishes. Flawless diamonds are exceptionally rare.
Flat Diamond
Trade term used to describe a diamond with a very shallow crown height and/ or pavilion depth. Flat round brilliant cut diamonds with a shallow pavilion tend to show a fish eye. Flat diamonds lack some brilliance and life.
Fish Eye
Unattractive donut-shaped white ring seen under the table of a round brilliant cut diamond with too shallow a pavilion depth. The ring is caused by the reflection of the diamond’s girdle. Diamonds with a fisheye lack brilliance, and show little life.
Flash Effect
Bright, vivid streak of colour found in the glass-like resin filling of diamonds treated by fracture filling.
Fire
Visible play of colours created by the break-up of light in a diamond. When light enters a diamond, it reflects off of the pavilion facets and refracts, or bends, into a rainbow of colours as it leaves the crown facets. Also known as dispersion.