Diamond Guide
Zavelli Diamond Education
Diamond Guide
Understanding what makes a diamond beautiful.
Choosing your diamond
A certificate tells you the grade. The diamond tells you the rest.
Diamond grading provides an important framework for understanding quality, but numbers alone do not determine how a diamond will look. Shape, proportions, facet arrangement and the way a stone interacts with light all contribute to its individual appearance.
The foundation
Understanding the 4Cs
Carat, colour, clarity and cut provide a universal framework for describing diamond quality.
Carat
Carat measures a diamond's weight rather than its visible size. One metric carat equals 200 milligrams.
Colour
Colour grading evaluates the presence or absence of colour within a diamond.
Clarity
Clarity considers internal inclusions and external blemishes and their appearance under magnification.
Cut
Cut considers the proportions and facet arrangement that influence brilliance, fire and visual performance.
Carat
Weight is not the same as visual size.
Carat is a measurement of weight. Two diamonds with the same carat weight can appear different in size when viewed from above because their dimensions, proportions and shapes may differ.
Cut
Beauty is shaped by light.
A diamond's proportions and facet arrangement influence how light travels through the stone and returns to the viewer. This contributes to brightness, fire and sparkle.
Colour
Understanding the D–Z scale
The traditional D–Z grading scale begins at D, representing colourless, and progresses toward increasing visible yellow or brown colour through Z.
Clarity
What lies within.
Clarity grading considers the size, nature, position, relief and quantity of clarity characteristics observed under 10× magnification. The visual importance of an inclusion can vary from stone to stone.
Elongated diamonds
Understanding the bow-tie effect.
Not every dark area is created equal.
Oval, pear and marquise-shaped diamonds can display a darker region across the centre known as a bow-tie effect. Its visibility and intensity vary according to the stone's proportions and facet arrangement. A prominent, persistent dark bow tie can influence the overall appearance of a diamond.
Shape & proportions
Two diamonds can share a grade and still look very different.
Shape describes the outline of a diamond, while proportions describe the relationship between its dimensions and facets. Individual proportions can influence spread, visual balance, pattern and the way the diamond interacts with light.
Laboratory-grown diamonds
Created differently.
Graded by the same fundamentals.
Laboratory-grown diamonds are created in controlled environments using technologies designed to grow diamond crystal. The two principal methods used are Chemical Vapor Deposition (CVD) and High Pressure High Temperature (HPHT).
The Zavelli standard
We look beyond the numbers.
A grading report provides essential information about a diamond, but we believe selection should also consider the stone as a whole. Visual balance, proportions, brilliance, pattern and overall appearance all form part of the final choice.
Independent grading
Understand your IGI report.
Learn how independent grading, report numbers and laser inscriptions help identify and document your diamond.
Explore IGI Certification
