Natural Diamonds
GIA will verify colour, clarity and carat weight within the tolerances stated below as well as creation and treatment. No other diamond attributes will be verified.
Authenticity Guarantee for Jewellery
Tolerance ranges for Jewellery Authenticity Guarantee
Authenticity Guarantee for Jewellery is limited to a review of claims regarding item quality and characteristics listed by the seller. These claims are assessed within defined ranges and tolerances. Reports, certificates, gifts to buyers as a bonus and free of charge and appraisals included in listings are not verified under the AG program and will not be validated.
Below is a detailed overview of those defined ranges and tolerances for mounted jewellery
Diamond clarity
GIA evaluates disclosed clarity grades for diamonds that are 0.15cts or larger, as long as the mounting allows. The clarity grades that are eligible for verification are VS2, SI1, SI2, I1, I2 and I3, while the clarity grades FL, IF, VVS1, VVS2 and VS1 will not be verified. The tolerance for all stated clarity grades is -1 grade. For example, a stated clarity grade of SI1 will pass verification if the apparent clarity is SI2.
NOTE: If the stated clarity grade falls in the FL-VS1 range but the clarity is obviously lower, the item will fail verification.
Eligibility
- Only diamonds 0.25 carats or larger are subject to colour verification.
- Diamonds smaller than 0.25 carats will pass for colour without colour assessment.
Colour Verification for D–M (colourless to Faint)
- Colour grade claims that fall within the range D to M will be verified within the specific letter grade range.
- Tolerance: Experts allow a -2 letter grade tolerance from the listed colour.
Example: If the listing states G, and the expert determines the colour is most likely I, the diamond will pass verification.
If the Seller states a colour range, experts will verify against the lowest grade in the range.
Colour Verification for N–Z (Very Light to Light)
- Colour grade claims that fall within the range N-R will be verified as falling within the Very Light range.
Example: If the listing states N, and the expert determines the colour falls within the Very Light range, the diamond will pass verification.
- Colour grade claims that fall within the range S-Z will be verified as falling within the Light range.
Diamond Carat weight estimation
Stones weighing 0.40 ct or more per stone have an acceptable tolerance of -10%. Stones that weigh less than 0.40 ct have an aggregate tolerance of -25%.
GIA will not assess the accuracy of carat weight disclosures for individual stones set in jewellery and weighing under 0.20cts, or for an aggregate stone weight under 0.20cts.
Diamond Treatment
A Diamond expert will verify if a particular treatment is present or not in the diamond as well as the nature of the treatment to assess its stability. The results will be verified against the listing and depending on whether the details about the treatment are disclosed or not, the expert will proceed as follows:
- GIA will not verify stable colour treatments for both D-Z and coloured diamonds.
- GIA will verify the presence of unstable treatments such as clarity enhancement, and coating, unless detection is prohibitively limited by the mounting.
- If the listing discloses the presence of an unstable treatment, GIA will not verify clarity and colour of the diamond and should all other verified criteria be aligned with the listing, the item will pass verification.
E.g.:
- Fracture filling: not permanent or stable
- Laser drilling: permanent
Laboratory Grown Diamonds
For laboratory grown diamonds the clarity and the colour statements made by the seller, will not be verified. GIA will verify carat weight within the tolerances stated above as well as creation and treatment. No other diamond attributes will be verified.
Coloured Stones
Coloured stones colour
For coloured stones, experts will confirm basic hues. Any trade term which describes specific colours and qualities of gemstones that are typically assigned to gemstones of superior quality and rarity such as Royal blue, Pigeon blood or Padparadscha will not be verified. .
Coloured stones carat weight estimation
Stones weighing 0.40 ct. or more per stone have an acceptable tolerance of -10%. Stones that weigh less than 0.40 ct. have an aggregate tolerance of -25%.
GIA will not assess the accuracy of carat weight disclosures for individual stones set in jewellery and weighting under 0.20 cts, or for an aggregate stone weight under 0.20 cts.
Assembled stones
Assembled stones are stones constructed out of two or more materials and are not eligible for Jewellery Authenticity Guarantee.
Common assembled stone types include:
- Doublet: A doublet consists of two joined segments.
- Triplet: A triplet has three segments, or two segments separated by a layer of coloured cement.
Gemstone treatments
Gemstones are commonly subjected to treatments which may be considered stable or unstable.
GIA will not verify claims regarding common treatments that are stable, such as heat treatment or irradiation.
GIA will verify the presence of unstable treatments such as clarity enhancement, glass filling, coating, and dyeing, unless detection is prohibitively limited by the mounting or requires advanced testing beyond the scope of standard examination. .
Stone Testing – random sample
For a jewellery item with multiple stones of the same species, GIA will test/verify a sample for identity, creation and treatment. If a jewellery item has multiple stones of multiple species, GIA will apply the same principle and test/verify a sample for each species. GIA will randomly test up to 5 gemstones.
Undetermined results
In some cases, if it’s not possible to determine whether an item is unstable or has been treated using then-current techniques and technology, treatment status of the item is undetermined and will pass this verification step.
The creation of coloured stones will not be verified if the total carat weight for the species is less than 0.20 cts.
Example: A necklace features three rubies with a stated weight of 0.05 cts each. The stated total carat weight for the species is 0.15 cts. The creation of the rubies will not be verified.
The natural or laboratory-grown origin of all varieties of quartz cannot be determined under Authenticity Guarantee.
Country of origin will not be verified for any gemstone.
Pearl
Pearl verification is focused on the determination that the material being verified is in fact pearl, rather than an imitation (e.g. fashioned shell, coated plastic, glass bead, etc.). A reasonable effort will be made to verify the accuracy of any claim regarding the shape, colour and size of a pearl.
- Items with 10 or less pearls = we verify all pearls
- Items with 10 or more pearls = we will select at random a range of 5 - 10 pearls to verify
If a mounting prevents us from separating pearls from Mabe/assembled pearls without advanced testing: we will use the term mollusk nacre materials for these items.
Claims that will not be verified:
- Any claim that a pearl is "cultured" or "natural".
- Any claim that a pearl originated in a specific environment (saltwater vs. freshwater)
- Any claim of treatments, trade terms and mollusk species.
- Any claim of classification or grades
Non-Gem Materials
GIA will not verify non-gem materials such as glass or plastics, including but not limited to paste, strass, rhinestones, diamante, opalite, goldstone, crystal, acrylic, and lucite.
Metals
Metal gram weight
If listed, the total gram weight of the metal-only items will be verified. Metal weights will not be verified on finished Jewellery items containing other non-metal materials (i.e., stones, enamel, etc.).
For metal only items:
- If the gram weight is 5% below stated weight, it will pass verification.
- If the gram weight is 5-10% below stated weight, it will require buyer approval. If a buyer rejects, the item will be returned to the seller.
- If the gram weight is 10% or more below the stated weight, the item will be returned to the seller.
Gold Plating
Gold plating and the base metal will be verified; however, the purity of the gold plating cannot be determined under Authenticity Guarantee.
Metal purity
The alloy of any metal may be inconsistent between different areas of a jewellery piece. For each jewellery item, GIA tests one or more areas of the metal at random for metal type and purity.
The following metals and metal purities are eligible for verification.
Please note, resizing an item may result in undisclosed composition and colour variation variances (i.e., metal alloys used to modify size may affect metal purity).
Silver purity conversion chart
Silver must be at least 92.5%+ Ster., Solid Silver or Sterling Silver.
Purity less than 92.5% silver cannot be marked as Ster., Solid Silver and/or Sterling Silver unless the item is a coin or coin silver having a minimum purity of 90% or more.
Tolerance: Please note there is no negative tolerance on purity.
| Common name | Parts of silver | % of silver purity | Fineness |
|---|---|---|---|
| 70% Silver | 700/1000 | 70% | 700 |
| 80% Silver | 800/1000 | 80% | 800 |
| Coin | 900/1000 | 90% | 900 |
| Sterling Silver | 925/1000 | 92.50% | 925 |
| Brittania | 958/1000 | 95.80% | 958 |
| Fine or Pure Silver | 999.9/1000 | 99.90% | 999 |
Gold purity conversion chart
Gold must be at least 9ct to be eligible
Tolerance: Please note there is no negative tolerance on purity
| Number of Carats | Parts of gold | % of gold purity | Fineness |
|---|---|---|---|
| 9k, 9Ct, 9 Carat, 9K Gold, 9Ct Gold,9 Carat Gold | 9/24 | 37.5% | 375 |
| 10k, 10Ct, 10 Carat, 10K Gold, 10Ct Gold, 10 Carat Gold | 10/24 | 41.7% | 416/417 |
| 11k, 11Ct, 11 Carat, 11K Gold, 11Ct Gold, 11 Carat Gold | 11/24 | 45.8% | 458 |
| 12k, 12Ct, 12 Carat, 12K Gold, 12Ct Gold, 12 Carat Gold | 12/24 | 50% | 500 |
| 13k, 13Ct, 13 Carat, 13K Gold, 13Ct Gold, 13 Carat Gold | 13/24 | 54.1% | 541 |
| 14k, 14Ct, 14 Carat, 14K Gold, 14Ct Gold, 14 Carat Gold | 14/24 | 58.3% | 583/585 |
| 15k, 15Ct, 15 Carat, 15K Gold, 15Ct Gold, 15 Carat Gold | 15/24 | 62.5% | 625 |
| 16k, 16Ct, 16 Carat, 16K Gold, 16Ct Gold, 16 Carat Gold | 16/24 | 66.6% | 666 |
| 17k, 17Ct, 17 Carat, 17 Gold, 17Ct Gold, 17 Carat Gold | 17/24 | 70.8% | 708 |
| 18k, 18Ct, 18 Carat, 18K Gold, 18Ct Gold, 18 Carat Gold | 18/24 | 75% | 750 |
| 19k, 19Ct, 19 Carat, 19K Gold, 19Ct Gold, 19 Carat Gold | 19/24 | 79.1% | 791 |
| 20k, 20Ct, 20 Carat, 20K Gold, 20Ct Gold, 20 Carat Gold | 20/24 | 83.3% | 833 |
| 21k, 21Ct, 21 Carat, 21K Gold, 21Ct Gold, 21 Carat Gold | 21/24 | 87.5% | 875 |
| 22k, 22Ct, 22 Carat, 22K Gold, 22Ct Gold, 22 Carat Gold | 22/24 | 91.7% | 916/917 |
| 23k, 23Ct, 23 Carat, 23K Gold, 23Ct Gold, 23 Carat Gold | 23/24 | 95.8% | 958 |
| 24k, 24Ct, 24 Carat, 24K Gold, 24Ct Gold, 24 Carat Gold | 24/24 | 99.9% | 999 |
Platinum purity conversion chart
PLATINUM = Pt., Plat or Platinum if preceded by a number indicating parts per thousand of pure Platinum (95%+ purity does not require a number preceding mark).
Please note, purity range below 850 will not be verified.
Tolerance: Please note there is no negative tolerance on purity.
| Metal mark | Parts of platinum | % of pure platinum | Fineness |
|---|---|---|---|
| 850Pt. 850Plat. | 850/1000 | 85% | 850 |
| 900Pt. 900Plat. | 900/1000 | 90% | 900 |
| 950Pt. 950Plat. | 950/1000 | 95% | 950 |
| 999Pt. 999Plat. | 999/1000 | 99.9% | 999 |
Palladium purity conversion chart
Palladium = Pall., Pd. or Palladium if preceded by a number indicating parts per thousand of pure Platinum.
Please note, purity range below 500 will not be verified.
Tolerance: Please note there is no negative tolerance on purity.
| Marking | Parts of palladium | % of palladium purity | Fineness |
|---|---|---|---|
| 500Pd. 500Pall. | 500/1000 | 50% | 500 |
| 950Pd. 950Pall. | 950/1000 | 95% | 950 |
| 999Pd., 999Pall. | 999.9/1000 | 99.9% | 999 |
Item size
An expert will verify that the size of the item matches the size listed by the seller (i.e., inches, mm) or the size of any ring. Necklaces have a tolerance of +/- 1 inch. Bracelets and anklets have a tolerance of +/- ½ inch . Rings will have a tolerance of +/- 1 full ring size. Bangle size will not be confirmed.
Please note, resizing an item may result in metal purity and/or composition variances in the area that was modified for resizing purposes (i.e., metal alloys used to modify size may affect metal purity in sections modified).