Understanding Diamond Carat: Weight, Size and Value
Diamond carat measures weight, not visible size. Learn how carat weight, diamond shape, proportions and the 4Cs affect the appearance and value of a diamond engagement ring.
Diamond Education: Expert Guides to Choosing a Diamond
Understanding diamonds is easier when you know what affects beauty, quality, rarity and price. The Polished Diamonds Diamond Education hub brings together practical guides for New Zealand buyers choosing a diamond for an engagement ring, fine jewellery or custom design.
Start with our guide on how to choose a diamond, which explains the internationally recognised 4Cs: cut, colour, clarity and carat weight. Explore diamond carat to understand why weight and visible size are not the same, or learn how the D–Z diamond colour scale affects appearance and value.
Our guides also explain diamond grading and certification, including the role of independent laboratories such as GIA and IGI, and what to look for when comparing certified diamonds. For buyers considering different origins, our lab-grown diamond guide explains how laboratory-grown diamonds compare with natural diamonds in composition, grading, price and rarity.
Browse the articles below for detailed information about diamond cutting, ethical sourcing, pink and fancy-colour diamonds and other important characteristics. You can also explore our natural and lab-grown diamonds or view diamond rings designed and made in New Zealand. Each guide is written to help you compare diamonds confidently and choose the right stone for your design, preferences and budget.
