Quartz vs. Quartzite: Engineered Stone or Natural Stone

The names are one syllable apart and the materials have almost nothing in common. Quartz is made in a factory. Quartzite is cut from a mountain. Homeowners mix them up, and so do some price tags. This page explains the difference, then deals with the larger problem: a share of the stone sold as quartzite is something softer, and you can find that out with a glass tile and a lemon before you pay for it.

Two different materials

Quartz, or engineered stone, is ground quartz and other minerals bound with resin and pigment and pressed into slabs. It is consistent, non-porous and needs no sealer. How it compares with the other common natural stone is covered in quartz versus granite.

Quartzite is natural stone. The Natural Stone Institute describes it as a metamorphic rock formed from sandstone that can be of exceptional strength, density and hardness. Heat and pressure fuse the sand grains into a solid mass of the mineral quartz. It often has soft gray, white, gold or green veining, which is why people who love marble are drawn to it.

The naming problem

Stone is sold by commercial groups, not by strict geology. The Natural Stone Institute explains that the trade classifies stones by how they behave and perform, and gives examples of stones sold under a name that is not their scientific one. In its words, the key is performance.

That system works when the stone performs like its label. With quartzite it sometimes does not. Marbles and dolomitic marbles with a similar look are sold as "quartzite" or "soft quartzite", and they behave like marble: they scratch more easily and they etch. Sandstones that never fully fused are sold as quartzite too, and they are more porous. None of this is visible on a polished slab under showroom lights.

Three stones compared

How to check that a slab is true quartzite

Ask the stone yard for an offcut or a sample from the same bundle as your slabs, not a display chip from a different shipment. Then run two tests at home.

The glass test

On the Mohs hardness scale published by the National Park Service, quartz is 7, a glass plate is about 5.5 and calcite, the main mineral in marble, is 3. A stone made of quartz will bite into glass. A marble will not.

1. Find a sharp corner or broken edge on the sample.
2. Press it firmly against a glass tile or an old glass bottle and drag it.
3. Wipe the mark with your finger. A real scratch stays and you can feel it. A powdery streak that wipes off is the stone crumbling against the glass, which means the stone is the softer of the two.

The acid test

1. Put a slice of lemon or a few drops of vinegar on the polished face.
2. Leave it for fifteen minutes or longer, then rinse and dry.
3. Look across the surface toward a window. A dull or lighter patch where the acid sat is an etch mark, and the stone contains carbonate minerals.

Test more than one spot, including a vein. Some slabs are quartzite with carbonate veins or patches, and they will etch only there. A slab that passes both tests everywhere you try will behave like quartzite in a kitchen. If the purchase is large and the seller's answers are vague, a geology lab can identify a sample for certain.

Heat

Quartzite was made by heat and is unbothered by a hot pan. Quartz is the opposite: the resin binder can scorch, yellow or crack with thermal shock. If you want a pale, veined counter beside a range and you know pans will land on it, that is a reason to pay for quartzite or to consider porcelain or sintered stone. The Natural Stone Institute still recommends trivets on natural stone as a habit.

Sealing and daily care

Quartz needs none. Quartzite depends on the slab. A fully fused quartzite absorbs very little. Others take up water and oil readily, particularly at cut edges and around the sink. Put a few drops of water and cooking oil on your sample for ten to fifteen minutes. Darkening means the stone should be sealed with an impregnating sealer, which the Natural Stone Institute describes as a repellent that makes stone more stain resistant, not stain proof.

For cleaning, the Institute's guidance for all natural stone is a neutral cleaner, stone soap or mild dishwashing liquid and warm water. It says siliceous stones such as quartzite generally resist the acids found in kitchens, but still advises against acidic cleaners because a stone may contain traces of acid-sensitive minerals.

Cost and fabrication

Quartz sits in the mid to higher tier and is predictable to fabricate. Quartzite sits in the higher to highest tier. The slabs cost more, the stone is slower to cut, and veined slabs call for careful layout and sometimes extra material so the pattern flows. In JDI Construction's published planning tiers, premium quartz belongs to the Signature level and high-end stone to the Luxury level; the ranges are on the kitchen remodel cost page.

What to check before you buy quartzite

• A sample from your own slabs, tested with glass and acid in several spots.
• The water and oil drop test, to judge how much sealing it needs.
• Fissures and filled areas: ask which are natural and whether any cross a planned cutout.
• Whether your fabricator cuts quartzite regularly and how it prices mitered edges.
• Consecutive slabs from one bundle if the kitchen needs more than one.
• The finish: a honed or leathered face changes the look and the upkeep, as covered in countertop finishes, edges and thickness.

Who should choose which

Choose quartz if you want the veined look with the least upkeep, you are comfortable using trivets, the counter is out of direct sun and you would like the finished kitchen to match the sample exactly.

Choose true quartzite if you want natural stone with movement, you cook with heat, the counter gets sun, and you are willing to seal a more porous slab and pay a higher tier for material and fabrication.

Choose neither if the stone you fell for fails the acid test and patina would bother you. Go in knowing it is marble, or pick another slab.

For the wider field, return to the countertop overview. JDI Construction reviews stone choices with you during design, before cabinets are ordered; our Vancouver kitchen remodeling page explains how that process starts.