CIBJO term definitions

CIBJO Blue Book terms that apply to every gem material: weights, optical effects, fashioning, names, care, and disclosure and trade documents.

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Terms that apply to every gem material

Weights, grading sieves and pricing

Carat

the unit of weight (5.89) of a diamond, gemstones, synthetic stone, cultured pearl, one carat being equivalent to 200 milligram (1/5 gram).

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.11, p.21

Weight

mass of a gemstone (5.38) or an artificial product (5.3). NOTE - The SI (Système International) generally uses the term mass instead of weight. Mass is a measure of an object’s inertial property, or the amount of matter it contains. Weight is a measure of the force exerted on an object by gravity or the force needed to support it.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.89, p.29

Optical effects

Phenomenal stones

stones exhibiting asterism (5.6), chatoyancy (5.13), colour change (5.15) etc.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.62, p.26

Play of colour

an optical phenomenon consisting of a variety of prismatic colours, seen in a rapid succession as a cabochon cut gemstone is moved about.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.63, p.26

Chatoyancy

stones cut as cabochons that show a single distinct and shimmering line crossing the surface of the cabochon and is related to reflection effects from inclusions within the stone, are known as cat’s-eyes. They exhibit chatoyancy and are chatoyant (cha·toy·ant adjective). A stone exhibiting chatoyancy is sometimes referred to as a “phenomenal” stone.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.13, p.21

Asterism

stones cut as cabochons that show two or more distinct and shimmering lines that intersect each other, while crossing the surface of the cabochon and are related to reflection effects from inclusions within the stone, are known as star stones. They exhibit asterism and are asteriated (as·te·ri·at·ed adjective). A stone exhibiting asterism is sometimes referred to as a “phenomenal” stone.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.6, p.20

Aventurescence

an optical phenomenon a gem material exhibits when it displays bright or strongly coloured reflections of tiny platelets or flakes as the gemstone is turned.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.7, p.21

Adularescence

an optical phenomenon a gem material exhibits when it displays a floating, billowy, white or bluish light effect in certain directions as the gemstone is turned due to diffused reflection of the light at fine parallel layers inside the stone.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.1, p.20

Colour change

the property of gem materials that change from one apparent colour to another apparent colour when moving between different sources of light such as daylight equivalent (D65 or Illuminent C) and incandescent equivalent light (Illuminent A).

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.15, p.21

Labradorescence

an optical phenomenon which produces flashes of pure spectral colours that gradually changes as the gemstone is moved about in reflected light, caused by diffraction of light at alternating layers of exsolution lamellae of regular size.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.49, p.25

Fashioning, drilling and cleaning

Cut

the style or form in which gemstones and artificial products have been fashioned, i.e. emerald cut, brilliant cut, etc.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.22, p.22

Cutting

one of several normal lapidary practices (5.54) used to modify a gemstone.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.23, p.22

Polishing

a method to obtain a polish on gemstones and artificial stones, usually produced by friction or abrasion.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.64, p.26

Shape

outline of a gemstone when viewed perpendicular to the table facet.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.73, p.27

Names and trade terms

Commercial name

a name assigned for marketing purposes. See clause 4.2.4.4, 4.2.4 and clause 7 Annex B.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.17, p.22

a name assigned for marketing purposes; synonymous with a trade name. It may have global or regional significance.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.24, p.13

The books word this differently; each wording is given with its source.

Objets d’art

an object considered to be of artistic worth.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.55, p.25; CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.145, p.39; CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.70, p.18

Trade name

a name assigned for marketing purposes; a commercial name. It may have global or regional significance.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.96, p.21

Care and stability

Special care

additional care needed to preserve the appearance of natural materials (5.53), any treated materials or artificial products (5.3).

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.75, p.27

additional care needed to preserve the appearance of natural and cultured pearls, or artificial products (5.11) or any alteration that may have been applied.

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.190, p.44

additional care needed to preserve the appearance of natural materials (5.68) or artificial products (5.5), or any alteration which require general (5.45) or specific information (5.91), that may have been applied.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.90, p.20

The books word this differently; each wording is given with its source.

Stability

a measure of the ability of gemstones and organic substances to maintain their appearance under normal wear and care.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.76, p.27

a measure of the ability of gemstones and organic substances (5.150) to maintain their appearance under normal wear and care. The ability of a process or a treatment, including bleaching, bonding, dyeing, irradiating, oiling, staining, tinting and waxing, to retain its appearance in pearls and cultured pearls, under normal wear, repair, cleaning and/or display conditions, and after re-cutting. NOTE: Some pearls that are not subjected to the processes mentioned above may change in appearance over a period of time.

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.193, p.44

a measure of the ability of coral to maintain their appearance under normal wear and care.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.93, p.21

The books word this differently; each wording is given with its source.

Definitions are quoted verbatim from the cited CIBJO Blue Book; […] marks an excerpt, and the full definition is at the cited clause.

Disclosure, documents and trade practice

Disclosure and documents

Advertisement

the activity of attracting public attention to a product or business, as by announcements in the print, broadcast, or electronic media.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.2, p.20; CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.4, p.22; CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.1, p.10

Commercial document

any writing or electronic transmission that evidences, anticipates or concludes a commercial transaction, including any agreement, memorandum of agreement, purchase order, blanket purchase order, identification reports, blanket purchase agreement, purchase order acknowledgment, request for proposal, quote, offer, warranty, representation certification, guaranty, import documentation, packing list, bill of sale, memorandum of consignment or receipt and advertisements. Commercial documents include mandatory information of the seller, and when necessary the buyer.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.16, p.21

Any writing or electronic transmission that evidences, anticipates or concludes a Commercial Transaction, including any agreement, memorandum of agreement, purchase order, blanket purchase order, blanket purchase agreement, purchase order acknowledgment, request for proposal, quote, warranty, representation certification, guaranty, import documentation, packing list, bill of sale, memorandum of consignment, receipt and in advertising. Commercial documents include mandatory information of the seller, and when necessary the purchaser.

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.47, p.26

any writing or electronic transmission that evidences, anticipates or concludes a commercial transaction, including any agreement, memorandum of agreement, purchase order, blanket purchase order, identification reports, blanket purchase agreement, purchase order acknowledgment, request for proposal, quote, offer, warranty, representation certification, guaranty, import documentation, packing list, bill of sale, memorandum of consignment, receipt and advertisements. Commercial documents include mandatory information of the seller, and when necessary the buyer.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.23, p.13

The books word this differently; each wording is given with its source.

Disclosure

the act of providing all material information (5.51) to fully inform a purchaser prior to or during a final sale.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.25, p.22

The act of providing all material information (5.117) to fully inform a purchaser prior to or during a final sale.

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.61, p.28

the act of providing all material information (5.59). To fully inform a purchaser, prior to or during a final sale.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.33, p.14

The books word this differently; each wording is given with its source.

Frequency of occurrence

the rate of occurrence (according to current knowledge) for a treatment being applied to gemstones.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.35, p.23

Material information

any information that, if disclosed (5.25) prior to and or during the time of sale, would alter the value, saleability or desirability of materials listed in clause 3, including any care, cleaning and or maintenance requirements.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.51, p.25

any information that if disclosed (5.61), prior and/or during the time of sale, would either alter the value, saleability or desirability of a pearl listed in clause 3, including any care, cleaning and/or maintenance requirements.

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.117, p.34

any information that, if disclosed (5.33) prior to and or during the time of sale, would alter the value, saleability or desirability of materials listed in clause 3, including any care, cleaning and or maintenance requirements.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.59, p.17

The books word this differently; each wording is given with its source.

Trade Codes

codes used within the trade, consisting of one or more letters, to designate the treatment of gemstones and organic substances, and/or to explain special care. See clause 8 Annex C.

CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §5.81, p.28

a list used within the trade, consisting of one or more letters, for labelling treated gemstones and organic and biogenic substances. (See Clause 6).

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.204, p.46

a list used within the trade, consisting of one or more letters, for labelling treated gemstones and organic and biogenic substances. See Annex 7.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.95, p.21

The books word this differently; each wording is given with its source.

Frequency

the rate of occurrence (according to current knowledge) for a treatment being applied to pearls including bleaching, bonding, dyeing, irradiating, oiling, staining, tinting and/or waxing. Expressed as Unknown: Rarely: Uncommon: Occasionally: Common: Usually: or Always: in Clause 8.

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.75, p.29

General information

a no longer applicable method to provide information, at the time of sale, when materials had been subjected to an alteration (5.8) that required a verbal disclosure (see clause 4.1.2.1) and a general comment on a commercial document, see clause (5.47).

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.80, p.30

a method to provide information, at the time of sale, when materials have been subjected to a treatment that requires a verbal disclosure (5.33) and a general comment on a commercial document (5.23).

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.45, p.15

The books word this differently; each wording is given with its source.

Specific information

a method to provide information to consumers in all publications, advertisements, communications, commercial documents (5.47) and at the time of sale, when materials have been subjected to a treatment that requires a combination of a verbal and written disclosure see clause 4.1.2.1. and 4.1.2.2 Also see clause 4.1.2.

CIBJO Blue Book — Pearl Book (Pearl Commission 2024-1) (CIBJO): §5.191, p.44

a disclosure method to provide information to consumers in all publications, advertisements (5.1), communications, commercial documents (5.23) and at the time of sale, when materials have been subjected to a treatment that requires a combination of a verbal and written disclosure (4.1.1.1.2) […].

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.91, p.20

The books word this differently; each wording is given with its source.

Definitions are quoted verbatim from the cited CIBJO Blue Book; […] marks an excerpt, and the full definition is at the cited clause.