Composition Compared
Engineered quartz surfacing is typically made from crushed quartz in grits and powders — around 90–93% of the body by weight — dispersed in an unsaturated polyester resin matrix of roughly 7–10%, with pigments, and compacted in a vacuum vibrocompression process into slabs before curing and polishing. The high aggregate ratio is why it is hard and dense; the resin is why it is non-porous and why it does not tolerate high heat the way stone does.
Natural stone is quarried and cut, with no binder at all. Granite is an igneous rock, hard and comparatively dense; marble is metamorphosed limestone, softer, more porous, and reactive to acids. Both can contain natural fissures or inclusions that a uniform factory material does not.
Terrazzo is a composite going back centuries: aggregate such as marble chips, granite, glass or shell set in a binder. Traditional terrazzo uses a cementitious binder and is poured in place, ground and polished; modern epoxy terrazzo uses a resin binder, is thinner and lighter, and is more often precast into tiles or slabs. The binder decides most of its properties — cement terrazzo is porous and needs sealing; epoxy terrazzo is much less so.
- Engineered quartz: ~90–93% quartz aggregate, ~7–10% polyester resin, vibrocompressed
- Natural stone: quarried mineral, no binder, natural porosity and inclusions
- Terrazzo: aggregate in cement (porous, poured) or epoxy (denser, often precast) binder
How Composition Shows Up in Use
Porosity follows the binder. Resin-bound quartz and epoxy terrazzo are effectively non-porous and do not need sealing; cement terrazzo and natural marble are porous and do. Heat tolerance runs the other way: natural stone tolerates heat that would damage a resin binder. Repairability depends on whether the surface can be worked in place — natural stone and terrazzo can be reground and re-polished; resin-bound quartz is harder to repair invisibly once chipped. Weight tracks density: granite and cement terrazzo are heavy, epoxy terrazzo and quartz somewhat less so, and all three need cabinet support specified for the actual slab weight. Seams appear wherever a slab ends, in all three materials, which is where solid surface — formable and bondable — differs from the whole group.
- Porosity and sealing follow the binder
- Heat tolerance favors natural stone over resin-bound materials
- Stone and terrazzo can be reground in place; quartz chips are harder to hide
- All three are cut, not formed, so seams appear at every slab end
The Silica Question
Because engineered quartz is mostly crystalline silica, cutting, grinding and polishing it generates respirable crystalline silica dust, and silicosis among fabrication workers has become a documented occupational disease in several countries. The regulatory response has been sharpest in Australia, where work health and safety laws prohibited the use, supply and manufacture of engineered stone benchtops, slabs and panels from 1 July 2024; porcelain and sintered stone products, and finished items that need no further processing, are outside that prohibition. Elsewhere the material remains legal but fabrication is subject to silica exposure controls that a specifier should expect a fabricator to demonstrate.
For a project specifier this is a real consideration: whether a material can be fabricated on site or by a local shop in the destination market, and under what controls, now varies by jurisdiction. It is also one of the reasons a cast, resin-based solid surface — which is not a crystalline silica material and is shaped by casting rather than cutting slabs — sits differently in this conversation.
- Quartz fabrication releases respirable crystalline silica
- Australia prohibited engineered stone benchtops, slabs and panels from 1 July 2024
- Porcelain and sintered stone are outside that prohibition
- Check local fabrication rules and controls for the destination market
