Engineered quartz: compositions, grades and where it beats natural stone — and where not to use it

Engineered quartz is the most widely used “artificial stone” in modern projects: kitchen and bathroom countertops, reception desks, bar tops, wall panels, stair treads, window sills. It is chosen because it looks like marble or granite, yet does not absorb wine, coffee or oil, needs no sealing and is the same from batch to batch. But under one name you will find slabs with 93% quartz and slabs with 60%, with clean pigments and with cheap fillers. The difference shows up after a year: yellow stains, chipped edges, cracks from a hot pan.

This guide is for designers, hotel and villa owners, developers and buyers choosing stone for kitchens, guest rooms and public areas. We cover what engineered quartz is made of, which compositions, finishes and thicknesses exist, how it compares with granite, marble, acrylic and sintered stone, where it wins, where it must not be used, and what to fix in the contract when ordering from a factory.

What engineered quartz is

Engineered quartz (quartz surface, agglomerated quartz) is a composite of crushed natural quartz and polymer resin. Slabs are made by vacuum vibro-compression (a process historically developed by Italy’s Breton): the mix is placed in a mould, compacted under vibration and vacuum, then cured in a kiln at roughly 80–100 °C. The slab is then calibrated and polished.

Typical composition:

• Quartz — 90–93%. Several fractions, from fine flour to 2–3 mm grain. Quartz gives a hardness of about 7 on the Mohs scale — above marble (3–4) and comparable to granite (6–7).
• Resin — 7–10%. Usually polyester or an unsaturated-resin system; it binds the grains and closes the pores.
• Pigments and additives. Colour, UV stabilisers, antibacterial additives (in some lines), mirror and glass chips for sparkle.

The key quality parameter is quartz share and raw-material purity. The closer to 93%, the harder and more stable the slab. At 70–80% the rest is carbonate or glass filler, there is more resin, the surface is softer, and the risk of scratches and shrinkage is higher.

Typical properties (take exact values from the test report of your batch):

• Water absorption — below 0.05% (granite usually 0.1–0.4%, marble higher).
• Flexural strength — typically 40–70 MPa.
• Density — about 2300–2450 kg/m³.
• Heat resistance — roughly up to 150 °C for short exposure (the resin is the limit).
• Standard slabs — 3200×1600 and 3000×1400 mm; Jumbo formats up to 3300×2000 mm exist.
• Thickness — 12, 15, 20, 30 mm (sometimes 8 mm for wall cladding).

Types by appearance

Pattern is quartz’s strength: it is set at the mixing stage, so you can get looks nature does not offer.

• Solid colours (pure colours). White, grey, black, beige. The most consistent across batches and the most common for hotel rooms and kitchens. Black and dark colours show scratches and fingerprints more.
• Speckled (granite-look). Fine grain that hides dirt and light wear; the budget classic for commercial kitchens.
• Large chip and mirror chip. Sparkle, a “terrazzo” effect; reception desks, bars, decorative panels.
• Veined (Calacatta, Carrara, Statuario-look). Marble imitation. In budget lines the veins repeat and look “printed”; in premium lines the pattern runs through the full thickness and is harder to bookmatch.
• Concrete and stone-look. Matte grey, “cement” textures for loft and contemporary bars.
• Surface finishes. Matte (honed), polished, aged (suede, leather) and textured. Matte hides fingerprints and scratches better; polished shows colour more deeply but dulls faster.

Grades and classes: how to read offers

There is no single international classification of quartz “grades”: manufacturers split slabs into their own lines. In practice there are three tiers:

• Premium brands (Caesarstone, Silestone, Cambria, Technistone and similar): fixed palettes, 10–25 year warranties, branded certificates, high price.
• Mid-market factories (including Chinese suppliers for international buyers): own palettes, certificates on request, a much lower price.
• Mass-market “no brand” slabs: low quartz share, fillers, unstable colour and calibration.

For a project the brand matters less than verifiable parameters: quartz share, silica certificate, water absorption and flexural test reports, thickness tolerance (±0.5–1 mm) and calibration. Pay special attention to one batch: slabs from different mixes can differ in tone.

Comparison table: quartz, granite, marble, acrylic, sintered stone

Read the table like this: quartz beats natural stone on predictability and zero maintenance, but loses to it in heat and outdoors. If the project is an outdoor kitchen by the pool, look at granite or sintered stone. For countertop types in general, see countertops: quartz, acrylic, solid wood.

Where quartz beats natural stone

• Hygiene. No pores: wine, coffee, oil and marker do not soak in. This matters for restaurant kitchens, bars and breakfast counters.
• No sealing. Marble and granite need their protection renewed every 1–2 years; quartz care is water and a neutral cleaner.
• Consistent batch. Natural stone varies block to block; quartz is stable, so it is easier to agree with the designer and to supply large volumes (hundreds of rooms).
• Custom pattern. You can get a white “Calacatta” without the natural variation, or a solid colour matching the hotel brand.
• Predictable price per m². Less waste from block rejection, simpler cutting calculation.
• Impact and flexural strength higher than marble, which reduces breakage during installation.

Where quartz loses and where it is not used

• Heat. A pan off the hob, a dish from the oven, a fryer next to the countertop: the resin does not tolerate temperatures above ~150 °C; marks remain and cracks are possible. Professional kitchens use trivets or choose granite and stainless steel.
• Outdoors. In direct sun the resin yellows, and the surface fades and clouds. For terraces, facades and pool bar tops use granite, porcelain or sintered stone.
• Edge chips. If a sharp edge is hit, the chip is hard to repair invisibly; specify a rounded 2–3 mm edge.
• Stiffness and weight. A 30 mm slab weighs about 70–75 kg/m²; overhangs and islands beyond 600 mm need supports.
• “Marble” quality. Cheap marble-look versions have repeating veins and lack the depth of natural stone; for a lobby real stone is often better.
• Aggressive chemicals. Solvents, bleach and drain cleaners (very high or low pH) attack the resin and leave dull marks.

Thickness and edge: where corners are cut

• 12 mm — wall panels, vertical cladding and countertops with a substrate; the budget option, but the edge needs a reinforced apron.
• 15 mm — a compromise for bathrooms and counters.
• 20 mm — the standard for kitchen countertops in Europe and Asia, normally without extra aprons.
• 30 mm — the premium choice for islands, bar tops and reception; higher price, load and freight cost.

Corners are most often cut in three places: thickness (15 mm laid instead of 20 mm with strips glued on as an “apron”), quartz share (calcium carbonate added) and calibration (±2 mm thickness tolerance instead of ±0.5 mm, visible when joining). All of this can be seen on a sample and in the test report, not from photos.

Workplace safety and restrictions

The slab contains over 90% crystalline silica. The finished countertop is safe, but dry cutting, grinding and polishing create fine respirable dust that causes silicosis. That is why a number of countries, for example Australia from 2024, impose bans and strict limits on fabricating high-silica engineered stone.

What it means for procurement: work only with factories that cut wet and have extraction and PPE, and do not allow on-site finishing with a dry grinder. Check the destination country’s requirements for installation crews. On large projects, close the safety question before signing the contract.

Mini-case: kitchens and bathrooms in a 40-room boutique hotel

Brief: one countertop material for guest bathrooms and the restaurant kitchen, moderate budget, limited time. What was decided:

• Rooms (40 units). 15 mm quartz, solid light grey, matte finish, one batch for the whole project and 10% spare slabs for fitting.
• Restaurant kitchen. 20 mm quartz for the service area, stainless steel by the hob, trivets for hot items.
• Pool bar. Not quartz but 30 mm granite with a brushed finish because of sun and water.
• Contract. Quartz share at least 90%, thickness tolerance ±0.5 mm, silica certificate, reference samples, AQL inspection before shipment.

This scheme gives uniformity in the rooms and removes the main risk: yellowing and stains outdoors.

How to check a slab from a sample

A 100×100 mm sample and slab photos do not show everything, but several checks take an hour:

• Weight and sound. A 20 mm sample is noticeably heavier at high quartz content; tapped, it sounds dense with no “dead” zones.
• Scratch. A key or coin on the matte surface: a good slab shows no mark, a soft one leaves a groove.
• Stain. A drop of coffee, red wine and marker for 12–24 hours: after cleaning there should be no trace.
• Cross-section. The edge should show no layers, voids or density changes; the colour is uniform through the thickness.
• Heat test. Do not heat the sample to its limit, but place a hot cup: on cheap resins a ring appears quickly.
• Calibration. Measure thickness at five points with a caliper and compare with the tolerance.

Installation and care

Even the best slab is ruined by installation mistakes. Kitchen joints go not over the sink or hob but at supported points; the hob cutout is made with corner radii of at least 5–10 mm, otherwise a crack starts from the corner. The substrate must be flat, without sag, supported every 600 mm. Joints are filled with adhesive matched to the stone, and on veined patterns the vein is matched across the joint, which is why slabs are numbered at the factory.

Care is simple: water and a pH-neutral cleaner, a soft sponge. Do not use abrasive pastes, caustic alkalis or solvents. Fine scratches on matte slabs can be polished; on glossy ones they show more. For commercial projects allow a 5–10% slab reserve for installation damage and future repairs: in a couple of years finding the same tone from another batch is almost impossible.

What to fix in the contract when ordering from China

China is the largest producer of quartz slabs and finished countertops: factories are located in Guangdong (Foshan, Yunfu) and Fujian (Xiamen, Shuitou), and many work for export. To get quality rather than a lottery, specify:

• quartz share and resin type, certificates and test reports;
• slab size and thickness, tolerance and calibration;
• colour code and a signed reference sample, the “one batch per project” rule;
• finish (honed, polished, suede) and edge type;
• packing: wooden A-frames, impact protection, number of slabs per container;
• delivery terms under Incoterms (Incoterms 2020), staged payment and AQL inspection.

For customs, slabs and finished articles of artificial stone fall under Harmonized System (HS codes) headings such as 6810 (articles of artificial stone); the exact code depends on composition and degree of processing and is confirmed by the broker from the specification. More on the code system on the World Customs Organization page. Sea delivery takes 30–45 days after production.

For how to organise stone, tile and finishing purchases as a whole, read sourcing building materials from China and sourcing tile and porcelain from China.

How Dream View helps with selection and sourcing

We do not sell “our own” stone: we select vetted factories for your specification, order samples, check quartz share, thickness and calibration, sign a contract with Incoterms and staged payment, run AQL inspection and deliver door to door. The commission is a fixed 10%, savings on tile and stone against the local channel reach up to 70%, and the minimum order is from $100,000 per year. Tell us about your project and we will send a free estimate: China sourcing agent services, orders@dreamviewchina.com, +66 80 942 2230, t.me/dreamviewchina.

Conclusion: what to choose in your case

• Guest-room kitchens and bathrooms: 15–20 mm quartz, solid or fine speckle, matte finish.
• Reception and indoor bar: 20–30 mm quartz, veined or solid, rounded edge.
• Outdoor kitchens, terraces, pool: granite, sintered stone or porcelain, but not quartz.
• Professional kitchen: quartz for the cold zone, stainless steel or granite beside the hob.
• Lobby with “expensive marble”: natural stone or premium quartz with a through-body pattern.

The main rule: engineered quartz is not one material but dozens of compositions. Choose by quartz share, test reports, thickness and batch, not by name and a nice photo.