4C’s of Diamond Quality
Diamonds are graded by four characteristics: cut, carat (weight), clarity, and colour. All four of these properties determine how much a diamond is worth.
Cut: What is the proportion of the diamond? Ideally a round brilliant cut diamond’s width should be 60% of its depth. The better cut a diamond is the more light will be reflected back to the viewer’s eye and therefore the more it sparkles. A good cut is very important to it’s value. Cut also refers to the shape such as: round, pear, marquise, heart and oval. If you are having a diamond mounted, write down the measurements of your stone. Measurements never change. Measure the stone after it is mounted and verify that it matches the appraisal and/or certificate.
Carat: How big is the diamond? Larger diamonds often cost more per carat due to their size. There are 100 points to a carat. Hence a 50 point diamond is 1/2 a carat. (There are 5 carats to a gram.) Always get the actual point size of a diamond rather than a fractional weight. Sometimes jewellers will try to sell a .90 diamond as a 1 carat diamond. A .90 diamond should be substantially less expensive.
Clarity: How clear is the stone? Clarity ranges from flawless (perfect) to I (included). Here is a chart:
- Flawless: perfect inside and out
- Internally Flawless: may have minor blemishes on the outside
- VVS1, VVS2: have very very slight inclusions. VVS1 inclusions can only be seen through the pavilion. VVS2 inclusions are more visible.
- VS1, VS2: have very slight inclusions. VS1 inclusions are harder to see than VS2.
- SI1, SI2, SI3: have small inclusions
- I1, I2, I3: have inclusions visible to the naked eye
Colour: Diamond colours generally range from D – X for white and yellow diamonds. D is the whitest. Around S they become “Fancy” yellow Diamonds. One can also find green, pink, red, blue and brown diamonds – though these are usually irradiated.
Be certain to ask: Do you guarantee the colour and clarity of your stones?
How to Examine a Diamond
To accurately judge the quality of a diamond, it is advisable to use more than the naked eye. Here are common ways to examine a diamond.
Microscope/Loop: To examine inclusions, one uses either a microscope or a 10x magnifying glass called a jeweller’s loop. This enables one to see inclusions in stones. Most dealers will let you use theirs.
Diamond Tester: A diamond tester uses light to verify that the stone you are examining is really a diamond. It does not guarantee quality — just the type of stone. Most testers will still work when the stone is mounted.
Certification: If you are unsure of your diamond knowledge or the jeweller you are buying from, get a certified Diamond. The best known and reliable certification is from GIA (Gemological Institute of America) or EGL (European Gemological Laboratory). Be aware that certificates will cost you an extra $100-$200 on average.
How Diamonds are Treated
Diamonds are often treated. If you are concerned about getting true value for your money, know what you are getting.
Filled for clarity: Diamonds with inclusions are sometimes filled with glass to make them appear clearer. Yehuda Diamonds have undergone this treatment. Filler can be damaged by heat, ultrasonic cleaning, and by re-tipping. The filling does not repair the inclusion, it just makes it less visible.
If you look at a filled diamond closely, rotate it under light, you should be able to notice a bluish flash. Yehuda will usually refill your diamond for free if it is ever damaged. Check for guarantees before buying such a diamond.
Irradiated for colour: Can be affected by heat.
Painted for colour: Can be painted to offset a yellow tinge. The paint wears off rather quickly. (Please note these are EXTREMELY rare, as it would have to be someone you would never see again selling the stone)
Fracture Filled: Laser Process: As late May 1999, newly treated diamonds will be sold in the market. These diamonds have been lasered to remove imperfections and then are filled. This process was developed by General Electric for LKI.
Ask if the diamond you are considering buying is treated. Getting a notarized statement from your jeweler saying that your diamond in not treated is recommended. This is like having the jeweler swear under oath that to his/her knowledge that the diamond is not treated.
How to Care for your Diamonds
Diamonds are often thought to be unbreakable. Unfortunately, this is not the case. Here are some useful handling and care tips.
Diamonds are brittle: If you hit a diamond hard, they WILL crack or chip if mishandled. Don’t wear your diamond when doing rough work.
Storage: Store diamonds separately. When stored with other jewellery, diamonds may scratch other jewellery (or each other).
Cleaning: The best method for cleaning is a jeweller’s polishing cloth. Most jewellers will clean your diamond ring for free if you are making another purchase in the store.