Pink Diamond Glossary
Familiarise yourself with Pink Diamond Terminologies
Below is a collection of terminologies used in the diamond industry. Feel free to familiarise yourself.
A common term used in the diamond industry to refer to four overall factors – Colour, Cut, Clarity and Carat Weight – used to determine the relative value of a diamond.
A white coloured surface scratch or flaw, possibly caused by contact with materials as hard as a diamond. Also, an area of unpolished surface seen at a facet junction as a result of wear.
A document listing a basic description and an approximate retail replacement value of an item which is generally used for insurance purposes. A reputable appraiser or gemological grading lab.
Be wary of appraisals that seem inflated or the diamond seems to be overgraded – look for a reputable appraiser or grading lab.
Updating your appraisal every few years ensures you are adequately covered for any loss, theft or damage in the event of an insurance claim. In addition, a current appraisal will give you a starting point if you are considering reselling your jewellery or diamond/s.
The brand name given to the rare red, purplish red, blue and pink diamonds that are only found in the lamproite deposits of the Rio Tinto Argyle mine, located in the East Kimberley region of Western Australia.
Any coloured Argyle diamond that is identified by a unique number laser inscribed on the girdle and recorded in the Argyle Pink DiamondsTM database.
Non-Argyle refers to Type IIa fancy coloured diamonds that are not from the Rio Tinto Argyle mine.
Argyle-origin is a diamond that is a Type Ia fancy coloured diamond. Origin diamonds are typically from parcel lots or seconds, of polished and rough diamonds sold at auction, or being less than 0.08 carats are not inscribed with a unique identifying lot number.
An atelier is a private workshop or studio where fine arts are created. Assistants, students and apprentices are supervised by a principal master producing pieces that are generally distributed branded in the founding artisan’s name.
An auction is a sales event where prospective buyers, known as bidders, place bids for an item or parcel of items. An auction may be a public, private or invitation only. Bids may be open or closed.
An open bid auction starts with an opening figure which increases incrementally as bidders challenge an existing bid until a final offer is unchallenged within the timeframe allowed. Sotheby’s and Christie’s are both auction houses for the fine arts and hold public and private auctions for collectible diamonds.
In a closed bid auction, interested parties submit their offers in the form of a sealed bid so the amounts submitted are unknown to bidders. While generally run as a first-bid auction, subject to rules outlined before the event, further rounds of bidding may occur if the seller is not satisfied with the previously submitted offers.
A baguette is generally a long slender rectangular shape with either straight or tapering sides with 14 facets.
These are features appearing on the exterior or surface of a diamond such as nicks, scratches and abrasions. Many of these marks can be polished out as they evolve from rough to the finished stone.
This is one of the steps in cutting a rough diamond where the first eight facets are made, setting up the symmetry and proportions of the finished diamond.
The term blue diamond describes natural diamonds that present with a blue or violet appearance due to evidence of boron, hydrogen, irradiation or inclusions. First found in India, these fancy colour diamonds are now mainly found at the Cullinan mine, South Africa and the Argyle mine, Western Australia.
Boron is a chemical element with the symbol B and atomic number 5. As it is chemically similar to carbon, the element of which diamonds are made of, boron is able to replace carbon atoms displaced during the formation of a diamond’s crystalline structure. Its presence in a diamond’s matrix affects the transmission of white light through the stone. Simplistically, if sufficient boron is ‘absorbed’ then the diamond will display a blue hue.
Defined as the intensity or overall level that a diamond reflects white light from a light source, brilliance is measured in the face-up position.
A high brilliance is an indication of a very good or excellent cut grade where the cutter balanced the diamond’s clarity with its proportions and symmetry.
Brilliant is a style of cut used to enhance a diamond’s brilliance. Diamonds featuring this style have triangular or kite shaped facets that radiate from a center (usually an octagonal) table out to the girdle edge of the diamond’s crown and pavilion.
While the Round Brilliant is the most common cutting technique used, fancy shape diamonds can be treated to this style resulting in the likes of a modified square brilliant known as the princess cut.
The cutting of the final facets on a diamond which include the upper and lower girdles and star facets.
The process of bruting or girdling, and the rounding of elliptically shaped diamonds, is performed by this specialist, who attaches two roughs to discs and spins the surfaces of each diamond against the other.
This is an inclusion that breaks the surface of a diamond from the interior of the stone and may appear as a crack or feather like.
Often equated with size for retail purposes, the term carat actually means the weight of a diamond. It is a standardised measurement and one (0.01) carat is precisely 200 milligrams (mg) so a 0.10 carat diamond weighs 20 mg. Also see Point.
The 15th most abundant element in the earth’s crust, the chemical symbol for carbon is C. This element has a unique ability to bond its atoms together in a variety of ways producing forms with very different physical properties. Two well known examples are diamond and graphite. Diamonds are translucent or transparent, a poor conductor of electricity and one of the hardest substances known to man. Graphite is opaque, conducts electricity and is soft enough to streak on paper. The carbon composition of both of these forms allow for a very high capacity to conduct heat and makes them chemically resistant.
An inclusion where dark or black specks of graphite, or a group of non-carbon crystals are found in a diamond. Also called black pique, they are often visible to the eye affecting the value of a stone. It is worth noting the extreme conditions under which diamonds form are also the conditions in which graphite forms.
An inclusion presenting as an open break at a diamond’s surface which may form from a feathering crack inside diamond or when an included crystal drops out during polishing.
A document provided by a gemological grading laboratory; an independent gemologist; a valuer; a jewellery crafter or a jewellery retailer. Established to create a verifiable record of a particular diamond’s characteristics such as weight, proportions, colour grade, cut, shape, clarity, origin and treatments, this document is used for insurance, investment or resale purposes. It may be referred to as a report, valuation or certificate of authenticity or origin.
Certificate of Authenticity
Issued for an Argyle diamond that has been inscribed by Rio Tinto’s Argyle Pink Diamond, this certificate contains the unique lot number that was inscribed onto the gemstone’s girdle as well as its Argyle grading system colour grade, carat weight, clarity grade, and shape.
An accredited specialist in gems who have been issued with a certificate as a graduate of a gemology program. These programs may be internationally recognized and delivered by an established grading laboratory, university, college or through an in-house industry leader.
Chain of Custody
As a means to ensure authenticity and origin, chain of custody refers to the chronological paper trail recording the sequential movement of a diamond from recognition of value and each processing stage through to the end buyer.
A shallow surface inclusion that begins at a facet junction, culet or a girdle edge where a piece of diamond has broken off. Besides lowering the value if left unaddressed, it might affect a diamond’s ability to stay intact.
The term can be confused with diamond chips, or very small pieces of diamonds which are referred to as ‘melee’.
Clarity refers to the degree to which inclusions or blemishes are present or absent from a gemstone and the overall effect these characteristics have on a diamond’s potential value.
Abrasion – an area of unpolished surface usually seen at a facet junction as a result of wear.
Bearded girdle – a series of tiny feathers at the girdle that can result from the cutting process
Bruise – a tiny area of impact accompanied by very small, root-link feathers; typically occurs at a facet junction
Carbon – a layman’s term, it refers to a black inclusion, sometimes called a carbon spot. It is typically a dark crystal or group of crystals and may not actually composed of carbon
Cavity – an angular opening created when part of a feather breaks away or when a surface-reaching crystal drops out or is forced out during polishing
Chip – a shallow opening caused by damage to the stone’s surface that typically occurs at the girdle, facet junction, or culet
Cloud – areas of tightly grouped pinpoints. Clouds can be large or small and vary in density
Crystal – a mineral crystal contained in a diamond
Etched channel – a rare characteristic resulting in a void caused by a dissolution event sometime during a diamond’s formation. A trigon is a form of etching
Extra facet – an additional facet usually put on to remove an inclusion close to the surface or to repair a minor issue
Feather – a common clarity feature caused by a slight separation in the crystal lattice of the diamond. General trade term for a break in a gemstone, often white and feathery in appearance
Grain center – a small, concentrated area of crystal distortion; can be white or dark, and might have a thread-like or pinpoint-like appearance
Graining – optical discontinuities that are observable with a 10x loupe or a standard gemological microscope. They can be internal or appear on the facet surface, colored or reflective
Indented natural – a portion of the rough diamond’s original surface that dips below a polished diamond’s surface
Inscription – laser inscribed numbers and/or letters, usually corresponding to a lab report number.
Internal graining – lines, angles, or curves that might appear whitish, colored, or reflective, or affect transparency at 10x; caused by irregularities in crystal growth
Knot – an included crystal that comes to surface and is polished as part of the facet. The outline of the crystal can usually be seen under magnification at the surface
Laser drill (hole) – a tiny surface-reaching tunnel with a thread-like appearance, produced by a laser light beam
Natural – a piece of the rough diamond crystal that is left on the stone, usually to save weight and usually at the girdle
Needle – a thin, elongated crystal that looks like a tiny rod at 10x
Nick – like a chip but smaller with no apparent depth
Pinpoint – a very tiny crystal that looks like a dot at 10x
Pit – a tiny opening that resembles a white dot with no apparent depth
Polish lines – fine parallel grooves and ridges left on a gem’s facet as a result of the polishing process
Polish mark – whitish film on the surface of a facet, caused by excessive heat during polishing. (also called a burn mark or burned facet)
Scratch – a linear abrasion on the surface of a diamond with no apparent depth
Surface graining – grain lines seen on a facet’s surface, brought out by polishing due to differences in hardness between the layers of the grain
Twinning wisp – series of pinpoints, clouds, or crystals that forms in a diamond’s growth place; associated with crystal distortion and twinning planes.
The clarity grade of a diamond is determined by where it fits in a scaled descriptor as assigned by a qualified or skilled observer. The examination of a diamond occurs under standardised lighting conditions using a 10x magnification device.
When evaluating a polished diamond for its clarity grading there are a number of factors that are also considered – size, number, position, nature (or type), and relief (or contrast of the inclusion to the diamond it is in). It is almost self explanatory that inclusions that are large, numerous, obviously darker or lighter than the host diamond, and/or centred under the table will reduce the grade given.
As an internationally trusted grader of gemstones, the GIA uses a scale which is divided into 6 definitions, with further divisions making a scale of 11 possible grades.
FL – Flawless – No inclusions or blemishes observed
IF – Internally Flawless – No internal inclusions observed, external blemishes confined to the surface
VVS – Very Very Slightly Included – Inclusions that are very difficult to see under the standardised conditions. This is divided into VVS1 and VVS2
VS – Very Slightly Included – Inclusions in this grade range from difficult to somewhat easier to see under the conditions. The grader can allocate a VS1 or VS2 clarity in this grade
SI – Slightly Included – Under standardised conditions, blemishes and inclusions can be easily seen by a grader, who can choose SI1 or SI2 in this grade.
I – Included* – A diamond with inclusions and blemishes that can be observed without magnification will be classed as I1, I2 or I3.
*Argyle diamonds are given a Pique grade instead of an Included, ie. P1, P2 or P3.
Be aware, not all graders use the same scale. For example, the American Gem Society places numerical values on their 12 descriptor grading scale by creating 3 grades across SI2 and I1 grades.
The point where a diamond has weak molecular bonds which can cause the diamond to break along a plane (or in a particular direction).
The act of cutting a diamond with a disc coated in diamond dust.
Affecting the brilliance of diamonds a ‘cloudy’ appearance is the result of many tiny inclusions clustered into a single, white cloud.
Refers to the body colour or the hue of the diamond when brilliance and dispersion are ignored. The most common diamonds known are colourless or clear.
A colourless diamond reflects white light from within its structure so the body of the diamond appears to be transparent. However, if certain conditions were met as carbon atoms were compressing into a diamond’s typical structure, the white light will appear as a colour. This occurs when elements such as boron, nitrogen, and hydrogen replace carbon atoms; or the crystal is irradiated; or clusters of minute impurities survive being super heated and crushed into (or out of) the crystal; or its structure is deformed while it is moving towards the surface of the earth.
So colourless diamonds are graded D to Z, where an increasing yellow to light brown appearance is observable because of the presence of nitrogen.
Fancy coloured diamonds cover a range of diamonds starting with those that display deeper yellows and browns than those graded Z, through to pink, red, blue, violet, grey, purple, orange, brown, olive and green. The saturation of these colours is also graded against a predetermined scale and compared to a collection of master diamonds.