Diamond Grading Exam Prep 2026 – Complete Practice Resource

Water describes how a diamond looks in terms of color and transparency. Historically, merchants used it to convey the stone’s appearance—how colorless or clear and bright it seems when light passes through it. A stone described as having good water would appear more colorless and transparent, giving a clean, watery look. This is about visual appearance, not about how large the stone is (weight), how much it costs (price), or how it glows under UV light (fluorescence).