A market-wide average across qualities and sizes. Your stone's value depends on carat, color, clarity, cut, treatment, and origin.
Agate is a banded variety of chalcedony (microcrystalline quartz) that forms in layers, producing concentric, fortification, moss, lace and landscape-like patterns in a wide range of colors. It is tough, relatively hard (around 6.5–7 Mohs) and extremely abundant, making it ideal for cabochons, beads, carvings and decorative objects.
Market averages will not price your stone. GemstoneAI identifies gems and jewelry from a photo, checks authenticity and treatment signals, and gives you a real market valuation in seconds. Free to try.
The GemstoneAI market index for agate is $11 per carat as of 2026-08-04. That is a market-wide average across qualities, not a quote for a specific stone. Individual value depends on carat, color, clarity, cut, treatment, and origin.
Visual tests alone are unreliable. GemstoneAI analyzes a photo of your stone for identity, treatment indicators, and authenticity signals, then estimates market value. It is free to try.
Over the past 30 days the agate index moved +0.6%. Gem prices move on supply, demand, and metal markets; treat any single stone as a collectible first and an asset second.