Stone library / Quartz & Silica / Chalcedony / AgateNanhong AgateEverything you need to know about nanhong agate: what it is, where it comes from, how to spot treated stones, and how to wear and care for it.Illustrative Nanhong Agate image. Appearance alone cannot confirm the exact material, treatment, origin, or value of a specific piece.What is nanhong agate?Nanhong Agate is a mineral variety with chemical formula SiO₂ (cryptocrystalline quartz — chalcedony with iron oxide). It has a Mohs hardness of 6.5–7, density of approximately 2.58–2.64 g/cm³, and refractive index of 1.53–1.54.What gives it its color?Iron oxide (Fe₂O₃) — hematite inclusions give the distinctive red colorWhere does it come from?Major sources include China (Yunnan Baoshan, Sichuan Liangshan) — exclusively Chinese material.Treatments and how to spot themHeat treatment and dyeing exist. 'Nanhong' specifically refers to high-quality red agate from southern China with a waxy luster.Important: Visual clues such as inclusions, color patterns, or surface features can provide preliminary observations, but they cannot replace refractive index, specific gravity, microscopic examination, and laboratory testing for a definitive identification. Treat visual clues as starting points, not final answers. Jewelry and care tipsWith hardness 6.5–7, nanhong agate is suitable for rings, pendants, earrings, and bracelets. Clean with warm soapy water and a soft cloth. Avoid ultrasonic cleaners unless the stone is known to be fracture-free. Store separately from harder gemstones.Cultural beliefs and symbolismNanhong Agate carries cultural meaning across many traditions — these are folkloric and cultural traditions, not scientifically verified properties. Its associations vary by culture, and its use in astrology, chakra, or feng shui contexts should be understood as cultural expression rather than factual claims.What affects its value?Price is determined by color saturation, clarity, cut quality, and size. Before buying: ask the seller to confirm the material identity, treatment status, dimensions, and return policy in writing.Use this guide as a starting pointFor a costly or disputed stone, ask for species, treatment, and origin information in writing. An independent laboratory report is stronger evidence than a marketing phrase.Return to Quartz & SilicaPrevious guideMorganiteNext guideNephrite JadeSources: GIA reference and the GemVerity editorial method. This is an educational guide, not a gemological identification report. Cultural beliefs described above are folkloric traditions, not scientific guarantees.