Budget is the first thing to consider, as the price of diamonds knows no bounds. As the saying goes, "as big as the bowl, as much rice can be filled," because the price of diamonds is limitless.

1. The 4Cs of Diamonds:

The "4Cs" are the standards for assessing the value and quality of a diamond. The "4Cs" stands for Carat weight, Clarity, Color, and Cut. By considering these four aspects, you can better understand the value and quality of a diamond. The price of a diamond is determined by its weight, color, clarity, and cut.

1.1. Color:

The Gemological Institute of America divides the color grades of diamonds from D to Z. D color is the most valuable, as diamonds closer to D color are more transparent (colorless), hence more valuable.

Diamonds from K to Z gradually become yellowish, which is noticeable to the eye, so it's not recommended to purchase them. However, many untrained individuals may not discern the color differences between diamonds rated from D to J.

1.2. Carat:

The higher the carat value, the larger the gemstone. Larger gemstones are rarer and thus more expensive per unit.

"Carat diamonds" typically refer to diamonds that are 1 carat or larger. When you visit a jewelry store and compare diamonds with the same color, clarity, and cut, you'll notice that a 50-point diamond is nearly twice as expensive as a 40-point one, and a 2-carat diamond can be several times more expensive than a 1-carat diamond. This is due to the carat premium in gemstones, with prices significantly rising at multiples of 5 or 10.

1.3. Clarity:

Diamond clarity is primarily determined by the quantity, size, shape, and color of inclusions. The fewer the inclusions, the higher the clarity, resulting in more brilliance and sparkle.

Internationally, diamond clarity is categorized into six major grades which can be further subdivided into several smaller grades.

1.4. Diamond Cut:

The diamond cut is the only parameter in diamond grading that can be manually controlled.

A good cut can even mask the flaws and shortcomings of a diamond, making it appear more radiant. Therefore, many people consider diamond cut as the primary focus when purchasing diamonds. Diamond-cut grades include Ideal, Excellent, Very Good, Good, Fair, and Poor.

2. Diamond Identification: Certification

The "identity card" of a diamond is its certificate, which proves whether the diamond is genuine, whether it has undergone artificial enhancement, and the grades of the aforementioned 4Cs parameters.

Diamond Certificates:

International certificates include those from the Gemological Institute of America (GIA), Hoge Raad voor Diamant (HRD), and the International Gemological Institute (IGI).

The Gemological Institute of America (GIA) is the most authoritative diamond grading institution globally, and diamonds with its certificates are generally the most expensive.