Onyx

When sourcing Onyx, the primary value driver is translucency and color uniformity. High-grade Onyx should have a consistent crystalline structure that allows for even light transmission when back-lit. Buyers must check for natural fissures or 'dry veins'; while common in natural stone, excessive cracking can compromise structural integrity. Ensure the slabs are mesh-mounted on the back for reinforcement and have a high-gloss polished finish (90+ gloss units) to enhance the stone's natural depth.

Onyx is a softer stone (typically 3 on the Mohs scale), so it is vital to verify its Compressive Strength (ASTM C170) and Water Absorption rate (ASTM C97). For international projects, ensure the supplier provides a Certificate of Analysis (COA) and complies with EN 14617 standards for agglomerated stone if sourcing engineered variants. For natural Onyx, a Material Safety Data Sheet (MSDS) is often required to confirm the absence of hazardous radiation or chemicals used during the resin-filling process.

Onyx is primarily used for high-end interior aesthetics rather than structural load-bearing. Common applications include back-lit feature walls, luxury countertops, and vanity tops. Because it is acid-sensitive and porous, it requires a professional-grade impregnating sealer before installation. For commercial flooring, it should only be used in low-traffic areas to prevent scratching and loss of luster.

Onyx is extremely brittle and prone to breakage during transit. It is mandatory to use reinforced 'A-frame' wooden crates that are IPPC fumigated. Slabs should be separated by polystyrene or foam sheets to prevent friction. We strongly recommend purchasing All-Risk Marine Insurance and requesting the supplier to provide loading photos and videos to ensure the containers are braced correctly to prevent shifting at sea.

Focus on 'Book-matching' capabilities and yield rates. Since Onyx is expensive, negotiate based on usable square footage rather than gross slab size. Ask for high-resolution photos of the exact blocks or slabs currently in stock, as natural patterns vary significantly. For large projects, request a dry-lay inspection where the supplier lays out the slabs on the factory floor for your approval via video call before final packing.

Given the high unit price of Onyx, utilize secured payment terms such as Letter of Credit (L/C) or escrow-based services. Never transfer full payment upfront; a standard industry practice is a 30% deposit and 70% balance against the Bill of Lading (B/L) after a third-party quality inspection (like SGS or Intertek) has verified the stone's quality and quantity at the loading port.