# GIA Diamond Reports: What They Say and How to Check One > What a GIA diamond report records, how the 4Cs are graded, what changed for lab grown stones in 2025, and how to check a report number before you buy a diamond ring in Dubai. Canonical: https://mazimo.ae/guides/gia-diamond-reports ## Key facts - **1931.** GIA has been active since 1931, as a nonprofit laboratory independent of commercial interests. - **D to Z.** GIA's colour scale. D is colourless; the letters run down to Z, a light colour. - **FL to I3.** GIA's clarity scale, from Flawless through the VVS, VS and SI grades to Included. - **Report Check.** Type the report number on gia.edu and compare every line with the paper in your hand. ## A nonprofit laboratory that wrote the grading language The Gemological Institute of America, GIA, describes itself as a nonprofit organisation that works independently of commercial and private interests, and it has been active since 1931. It created the 4Cs of diamond value, colour, clarity, cut and carat weight, and the International Diamond Grading System that most of the diamond trade still uses as its common language. That matters to a buyer for one plain reason. When a seller says a diamond is a G colour or a VS2, the sentence only means something because a laboratory somewhere defined those letters. GIA is where the D to Z colour scale and the FL to I3 clarity scale come from, and a GIA report is read against them. ## What a GIA report records A GIA report belongs to one stone. It does not describe a ring, a brand or a price. It records what the laboratory measured and graded, and it prints a report number that you can look up. - The report number and the date of the report. - The shape and cutting style, for example round brilliant, oval or emerald cut. - The measurements in millimetres and the carat weight to two decimals. - The colour grade and the clarity grade, with a plot that maps the inclusions: a fingerprint of that one stone. - For round brilliants, an overall cut grade, with the polish and symmetry grades. - The fluorescence line and any comments, including whether the stone has been treated. ## The four Cs, as GIA grades them Colour is graded from D, colourless, down the alphabet to Z. The difference between neighbouring letters is small enough that two people will not agree by eye, which is why a laboratory with a master set and a fixed light is used. Clarity describes the inclusions and blemishes seen at 10x magnification: Flawless and Internally Flawless, then VVS1 and VVS2, VS1 and VS2, SI1 and SI2, and I1 to I3. Where an inclusion sits changes what you see, so two stones with the same grade can look different. Our guide to eye clean diamonds explains how to read that. Carat is weight, not size: one carat is 200 milligrams. A 0.98 carat stone and a 1.00 carat stone look almost identical, so the exact figure on the report is the one to compare. ## Round brilliants carry a cut grade; other shapes do not GIA gives an overall cut grade only to standard round brilliants, from Excellent down to Poor. For an oval, a pear, a marquise, an emerald or a cushion the report gives polish and symmetry grades instead, and the buyer judges the outline and proportions with the eye. A missing cut grade on a fancy shape is not a fault of the stone or of the report; it is how GIA reports those shapes. Our Journal explains the difference between an Excellent and an Ideal cut on a round stone, and how to judge the length to width ratio of an oval, a marquise or a cushion. ## Lab grown diamonds at GIA: what changed in October 2025 GIA issues a separate report for laboratory-grown diamonds, the Laboratory-Grown Diamond Quality Assessment, in a format that is clearly different from the report for a natural diamond. The girdle of a lab grown stone it assesses is laser inscribed with the words Laboratory-Grown and the report number. Since 1 October 2025, GIA's reports on colourless and near-colourless lab grown diamonds give no colour or clarity grade. Each stone is placed in one of two categories. Premium means D colour, VVS clarity or better, Excellent polish and symmetry, and an Excellent cut on round brilliants. Standard means colour J or better, VS clarity or better, at least Very Good polish and symmetry, and at least a Very Good cut on round brilliants. Stones below that receive no assessment. So if a seller quotes GIA colour and clarity letters for a lab grown stone, look at the date of the report. A GIA report issued since the change does not give them. ## Check a GIA report in three steps A genuine report for a different diamond is an old trick, and laser inscriptions can be faked, so the paper alone proves nothing. Three checks close the gap. - Ask for the report number before you decide, and write it down. - Type the address of the laboratory's own website yourself, gia.edu, rather than following a link or a QR code printed on the paper, and enter the number in Report Check. Compare the weight, the measurements and the grades with the paper. - Where the stone is inscribed, read the girdle under a loupe of at least 10x and compare every digit with the report. A prong can hide part of the inscription once the stone is set, so the time to read it is before setting. ## A report grades the diamond, not the ring A diamond ring carries two documents that do two different jobs. The grading report describes the stone: shape, weight, colour, clarity, origin. A certificate of purity describes the metal: the karat, the weight in grams, and the hallmark inside the ring, 750 for 18K gold. Neither replaces the other. Every Mazimo certificate of purity carries a tracking code that you can check at mazimo.ae/track. The stone's grading report is the second document, and its number is the thing to ask for. ## Polish, symmetry and fluorescence: the lines people skip Polish and symmetry are graded from Excellent to Poor. They describe the finish of the facets: how smooth the surface is, and how exactly the facets line up. On a round brilliant they sit beside the cut grade; on every other shape they are the cut information the report gives you, so they deserve a look. Fluorescence is the glow a diamond can show under ultraviolet light. A report records it as None, Faint, Medium, Strong or Very Strong. In most stones it is invisible in daylight, and it is not a fault, but a strong glow can change how a stone looks in certain light, so it is worth knowing before you set the stone. Our Journal guide to diamond colour grades and fluorescence explains when it matters and when it does not. ## Five questions to ask before you pay A report is only as useful as the questions you ask around it. These five take a minute and settle most doubts. - Which laboratory graded this stone, and what is the report number? - What is the date of the report? For a lab grown stone, the date tells you whether the report gives colour and clarity grades or a Premium or Standard category. - Does the girdle inscription match the report number when you read it under a loupe? - Do the weight and measurements on the laboratory's own website match the stone and the paper? - Does the invoice repeat the laboratory, the report number, the shape, the weight, the grades and the origin, word for word? ## GIA reports at Mazimo Mazimo makes diamond rings to order in Dubai in 18K white, yellow or rose gold, in ring sizes 46 to 62, and the first resizing is complimentary. Tell us you want a GIA report and we will confirm the report number for the stone before you decide, so that you can check it yourself on gia.edu. If you would rather see the stone and read the report with us, book a private viewing at the boutique at Al Manal Center in Deira. You can also send the number of any report to us on WhatsApp and we will read it with you. ## Questions **What does GIA stand for?** GIA is the Gemological Institute of America. It describes itself as a nonprofit organisation that works independently of commercial and private interests, and it has been active since 1931. **Is a GIA report a valuation?** No. A report records what the laboratory measured and graded for one stone. It gives no price. A price depends on the stone, the setting and the seller. **Does every diamond come with a GIA report?** No. Many diamonds are graded by other laboratories, and small stones such as the pavé and halo stones around a centre diamond are rarely graded one by one. For those stones the invoice should give the total weight and the origin. **How do I check a GIA report?** Take the report number, type gia.edu into your browser yourself, enter the number in Report Check and compare the weight, measurements and grades with the paper. If the stone has a girdle inscription, read it under a 10x loupe and compare the digits. **Why does my oval or pear report have no cut grade?** GIA gives an overall cut grade only to standard round brilliants. For other shapes the report gives polish and symmetry grades, and the shape and proportions are judged by eye. **Did GIA stop grading lab grown diamonds?** Not entirely. Since 1 October 2025 it assesses colourless and near-colourless lab grown diamonds as Premium or Standard, without individual colour or clarity grades. **Is GIA better than IGI?** They are two independent laboratories, each with its own reports. GIA is the benchmark much of the trade uses for natural diamonds; IGI issues most of the reports that come with lab grown diamonds. Either is worth more than a paper you cannot check. Our IGI guide sets the two side by side. **Can I ask Mazimo for a GIA report?** Yes. Tell us which report you want and we will confirm the report number for the stone before you decide. ## Keep reading - [18K, 21K and 22K Gold Explained](https://mazimo.ae/guides/gold-karats) - [Ring Size Guide](https://mazimo.ae/guides/ring-size) - [Jewellery Care Guide](https://mazimo.ae/guides/jewellery-care) - [IGI Diamond Reports: What They Say and How to Check One](https://mazimo.ae/guides/igi-diamond-reports)