Why certifications matter when buying marble
The stone market looks similar on the surface but can differ enormously underneath: the same 'Spanish Beige' can vary in density, water absorption, radioactivity and heavy-metal content depending on quarry and factory. Certification exists so an independent third party verifies those objective figures, filtering out non-compliant stock. For Hong Kong homeowners that means three things: family health (low radiation, low emissions), durability (hardness and water absorption within spec), and a reference for future maintenance. Asking your supplier for certification is a reasonable request, not an excessive one.
What is CE certification? The EU market entry
The CE mark means a product meets EU requirements on health, safety and environment — stone must carry CE to enter the European market. For stone, CE mainly verifies compressive strength, water absorption, abrasion resistance, slip resistance and radioactivity. One point to note: CE is a market-access standard, not a premium grade — it means the stone cleared the safety bar, not that it is top-grade. Hong Kong does not mandate CE, but a supplier that certifies its stone shows its sourcing and production are third-party monitored, which is a meaningful quality signal.
Understanding ISO: it audits the company, not the slab
ISO certification verifies a company's management systems rather than a single product. The two common ones: ISO 9001 is a quality management system, meaning procurement, production and dispatch follow standardised, continuously improved processes; ISO 14001 is an environmental management system. When choosing a supplier, ISO 9001 matters most — a certified company delivers far more consistent quality. Always check the certificate's stated scope to confirm it actually covers stone processing and sales, not just a company name.
GREENGUARD and NSF: environmental and food-grade safety
GREENGUARD is a US low-emissions certification that verifies a product's indoor volatile organic compound (VOC) levels stay below safety limits — especially important for households with children, pregnant women or sensitive people, since some stone adhesives and sealers can emit VOCs. NSF certification usually appears on food-contact stone, such as kitchen countertops and dining tables, verifying the surface releases no harmful substances when touching food. Neither is common in Hong Kong, but asking 'do you have GREENGUARD or NSF' for a kitchen countertop helps you pick safer material.
Radiation testing: the biggest myth about natural stone
Many people worry that 'marble has radiation'. The reality: all natural stone contains trace radioactive elements, but most compliant products are far below safety limits — often lower than the tiles and concrete already in your home. Mainland China's GB standard classifies stone into A/B/C by radioactivity, with only Class A approved for indoor use; Hong Kong and the EU follow international standards. So the right question is not 'does it have radiation' but 'what is the reading and which class is it'. A reputable supplier can provide a third-party test report — the numbers speak for themselves.
How to verify certification in Hong Kong: four steps
Step one: ask the supplier for the certificate itself or a scan, never accept a verbal claim. Step two: check the company name on the certificate matches the company selling you the stone — certification cannot be 'borrowed'. Step three: look up the certificate number on the issuing body's website; this is the most decisive step and filters out most fakes. Step four: check the validity period, since certifications expire. As a quarry-direct manufacturer, HENGSHENG MARBLE holds complete, current certifications and can show them at our Mong Kok showroom or during a free measurement visit.
