Why do white granite and quartz composite sinks turn yellow？
2026-07-30
The fundamental reason for the yellowing of white granite quartz sink lies not in the quartz particles themselves, but in the resin component that acts as a binder. Quartz is stable, but as an organic material, resin can age and discolor under certain conditions.
Specifically, there are several main reasons:
Granite sinks are composed of resin and quartz sand, with PMMA-type acrylic resin being the preferred choice. PMMA resin has excellent stability and will not discolor over time.
The manufacturing process of granite sinks is also crucial; a thermosetting process must be used to ensure color stability.
Resin aging. Prolonged exposure to ultraviolet light (sunlight), high temperatures (such as direct exposure to a hot pot), or certain chemicals can alter the molecular structure of the resin, leading to decreased transparency and yellowing.
Stains and Pigment Deposition: Dark liquids such as coffee, tea, and soy sauce, or oil stains, if not cleaned promptly, will penetrate the surface or oxidize to form a yellow film.
Scale Accumulation: Calcium and magnesium ions in hard water will form scale, which will gradually turn yellow if not removed in time.
Improper Cleaning: Using steel wool will damage smooth surfaces; strong acids, alkalis, or bleach may corrode resin, causing discoloration.
Raw material quality issues: If the quartz sand itself is of low purity and contains iron impurities, or if the resin or glue is of poor quality, it may appear yellowish or easily turn yellow after leaving the factory.
To keep your white sink pristine, besides choosing a high-quality granite sink, avoid direct contact with hot pots, wipe water stains dry promptly, and clean with a neutral detergent and a soft cloth.
![granite sink]()
Specifically, there are several main reasons:
Granite sinks are composed of resin and quartz sand, with PMMA-type acrylic resin being the preferred choice. PMMA resin has excellent stability and will not discolor over time.
The manufacturing process of granite sinks is also crucial; a thermosetting process must be used to ensure color stability.
Resin aging. Prolonged exposure to ultraviolet light (sunlight), high temperatures (such as direct exposure to a hot pot), or certain chemicals can alter the molecular structure of the resin, leading to decreased transparency and yellowing.
Stains and Pigment Deposition: Dark liquids such as coffee, tea, and soy sauce, or oil stains, if not cleaned promptly, will penetrate the surface or oxidize to form a yellow film.
Scale Accumulation: Calcium and magnesium ions in hard water will form scale, which will gradually turn yellow if not removed in time.
Improper Cleaning: Using steel wool will damage smooth surfaces; strong acids, alkalis, or bleach may corrode resin, causing discoloration.
Raw material quality issues: If the quartz sand itself is of low purity and contains iron impurities, or if the resin or glue is of poor quality, it may appear yellowish or easily turn yellow after leaving the factory.
To keep your white sink pristine, besides choosing a high-quality granite sink, avoid direct contact with hot pots, wipe water stains dry promptly, and clean with a neutral detergent and a soft cloth.
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