Short answer.
- Quartz is engineered: crushed quartz bound with resin. It looks consistent, and the brands say it needs no sealing, but they also say to keep hot pans off it.
- Granite is natural stone. It's hard, it varies from slab to slab, and it may need periodic sealing.
- Quartzite is natural stone too, a metamorphosed sandstone. It often looks like marble but is far harder. Make sure what's sold as quartzite really is quartzite.
The right choice depends on what the buyer cares about most. The questions below help you find out.
At a glance
| Engineered quartz | Granite | Quartzite | |
|---|---|---|---|
| What it is | 70–93% quartz sand or aggregate, bound with polyester resin (NSI) | Natural stone. To a geologist, a coarse-grained igneous rock; in the trade, often "any hard stone that is not marble" (NSI) | Natural metamorphic rock made of metamorphosed sandstone (NSI) |
| Look | More consistent slab to slab; designed colors and veining | Natural variation, every slab different | Natural variation; often light, marble-like veining |
| Sealing | Brands say none needed (nonporous) | Often periodic sealing, depending on the stone | Depends on the stone's porosity |
| Heat | Brands advise trivets and hot pads | Top scores for hot pots in Consumer Reports' testing | No rating found from a source we trust; use trivets |
| Etching from acids | Follow the brand's care guide | Not the main concern; marble is the stone that etches | True quartzite doesn't etch |
Engineered quartz
What it is. The Natural Stone Institute (NSI) describes "manmade quartz surfaces" as "70% to 93% quartz sand or aggregate," with "polyester resin" binding the pieces together (NSI, 2019).
Why buyers choose it. The color is predictable, the sample is close to the slab, and there's no sealing. Cambria says its surface "requires no sealing, polishing, or reconditioning" and is "nonporous and nonabsorbent" (Cambria care FAQ). Caesarstone says its quartz is "engineered to be highly nonporous, and as such it is non-absorbent" (Caesarstone care).
What to tell them about heat. The resin is the weak point.
- Cambria: "Cambria may not withstand the direct transfer of heat from pots and pans and other cooking units," and it recommends a "closed-weave hot pad or solid trivet" (Cambria).
- Caesarstone: "Always place hot cookware on trivet and hot pads" (Caesarstone).
- A fabricator quoted by NSI called heat damage "the biggest drawback of manufactured quartz" (NSI).
Consumer Reports says quartz "survived spills, hot pots, knives, and more with top scores in our tests" (Consumer Reports, updated 2025-05-22). Lab results and manufacturer care advice answer different questions, though. Tell the buyer to follow the manufacturer's care guide, since that's what the warranty is written around.
Outdoor use. Before quoting an outdoor kitchen or a very sunny spot, check the brand's warranty for outdoor and UV exclusions.
Granite
What it is. NSI notes that "to a geologist, granite is one specific type of stone. It's a light colored, coarse-grained igneous rock," but "in the natural stone industry, 'granite' often means any hard stone that is not marble" (NSI, 2017). So two "granites" in your showroom can behave differently. Ask the supplier about the specific stone.
Why buyers choose it. Every slab is one of a kind, and it's durable. Consumer Reports writes that "like quartz, granite survived our spills, hot pots, knives, and more with top scores" (Consumer Reports).
Sealing. Consumer Reports says "granite needs periodic sealing for stain protection" (Consumer Reports). Not every granite needs it equally: NSI notes that "some granites, such as Absolute Black, may not require sealing, or will only need one application of sealer" (NSI, 2018).
A simple test you can show the buyer, quoted by NSI: "Put a little hot water on an area, let it sit for 10 to 20 minutes, and then wipe it off… If the stone darkens, it's still absorbing moisture" (NSI).
Quartzite
What it is. "Quartzites are made of metamorphosed sandstone" (NSI, 2019). It's "a metamorphic rock – one that's been baked into an extra-tough stone" (NSI, 2018).
Why buyers choose it. It often has the light, veined look people want from marble, with much more hardness. NSI says quartzite is "nearly twice as hard as glass and harder than the blade of a knife" (NSI). For reference, quartz rates 7 on the Mohs hardness scale (USGS).
Sealing. "Is sealing required for quartzite? It depends on the stone's porosity" (NSI). Where it is sealed, NSI advises sealing "all worked edges of the stone, not just the tops" (NSI).
Is it really quartzite? The mislabelling problem
This is the part that protects your shop's reputation. NSI warns that "some stones are often mislabeled as quartzite or 'soft quartzite' when they are in fact marble" (NSI). Marble etches when acids such as lemon juice or wine sit on it. True quartzite doesn't.
The tests NSI describes:
- Glass test. "True quartzites do not etch, cannot be scratched easily with a knife blade, and will scratch glass" (NSI). As NSI puts it, "anyone with a glass tile can easily tell the difference" between quartzite and marble (NSI).
- Ask your supplier for the geological identification of the stone, and test an offcut, not the buyer's slab.
If a buyer wants the quartzite look and will be squeezing lemons on the island, getting this right matters more than any other part of the sale.
Matching the material to the buyer
Five questions help:
- "Do you want every inch to look predictable, or do you love natural variation?" Predictable points to quartz. Variation points to granite or quartzite.
- "Are you OK with occasional sealing?" If not, quartz. Or a natural stone that passes the water test with little or no sealing.
- "Do hot pans go straight from the stove onto the counter?" Steer quartz buyers to trivets, and say so upfront.
- "Is it a marble look you're after?" Consider quartzite, and verify it's true quartzite.
- "Is any of it outdoors or in strong sun?" Check the warranty terms before quoting quartz.
Whatever they choose, the buyer should see the actual slab before fabrication for granite and quartzite, because every slab is different.
A note for fabricators: silica
Quartz is crystalline silica, and engineered quartz and quartzite are both mostly quartz (see above). Cutting, grinding and polishing them makes respirable silica dust. OSHA's permissible exposure limit for respirable crystalline silica is "50 μg/m3, calculated as an 8-hour TWA," with an action level of 25 μg/m3 (OSHA 29 CFR 1910.1053; construction work falls under 1926.1153).
CDC's MMWR reported "eighteen cases of silicosis, including two fatalities… among stone fabrication workers in four states." Most of those workers "worked with engineered stone, a manufactured, quartz-based composite material that can contain >90% crystalline silica" (MMWR, 2019-09-27). In February 2026 OSHA and NIOSH issued a joint hazard alert, "Worker Exposure to Silica during Countertop Manufacturing, Finishing, and Installation" (NIOSH Pub. 2026-101). Read it with your safety lead.
This is a shop-safety issue, not a sales talking point. It's here because the people reading this guide work in fabrication.
Show it before they choose
The fastest way to settle "quartz or quartzite?" is often to show both on the buyer's own counters. With Countertop Visualizer, your salesperson photographs the kitchen, taps a quartz and then a quartzite from your catalog, and sees each on the counters in about 20 seconds. Then the buyer goes to see the real slabs. Every render is an AI visualization, not a replacement for the slab. 7 days free, then $250/month.