Low Silica Quartz 2026: The Complete Guide to Q10 vs Q40 Standards

The quartz industry changed composition. Most people in the trade know that. What fewer people can clearly explain is what Q10 and Q40 actually mean, which products hit which threshold, and—the question fabricators keep asking—how much silica reduction is actually enough.

What Is Low Silica Quartz?

Low silica quartz is engineered stone that has replaced a significant portion of its traditional crystalline silica content with alternative minerals—typically recycled glass, feldspar, porcelain, or bio-resins.

Traditional engineered stone ran 90–93% crystalline silica by weight. Low silica products replace most of that content, landing in two primary tiers:

The "Q" rating system was popularized by Cosentino when it launched Silestone XM, and has since been adopted by major distributors including MSI and Dal-Tile as a practical labeling framework across the industry.

Why the Industry Shifted

Australia banned high-silica engineered stone outright in July 2024. That's the short version.

The longer version: a decade of silicosis deaths among countertop fabricators—workers in their 30s and 40s developing an irreversible, fatal lung disease from cutting and grinding quartz—created pressure the industry couldn't absorb quietly. Australian regulators moved first. California followed with an emergency standard in 2024 and a permanent Cal/OSHA standard in 2025. Federal OSHA has tightened enforcement nationally.

The math forced the industry's hand. At 90% silica, dry cutting or grinding engineered stone generates clouds of respirable crystalline silica (RCS) that are nearly impossible to control to safe exposure levels. Wet cutting helps, but doesn't eliminate the risk. Water-fed tooling and local exhaust ventilation help more. But cutting a 90% silica slab is a fundamentally different hazard than cutting a 10% silica slab.

That's the practical reality behind the Q-rating system—not marketing, not trend-chasing. Regulatory necessity.

How Q Ratings Actually Work

The Q in Q10 and Q40 refers to the maximum crystalline silica content in the finished slab, measured as a percentage by weight. A few things worth understanding before specifying or stocking these products:

"Less than" is the key phrase. Q40 products can land anywhere from 8% to 39% silica. Some Caesarstone Mineral colors approach 10%, others sit closer to 35%. The label tells you the ceiling, not the actual number. If exact silica percentage matters for your compliance program or project spec, request the Safety Data Sheet (SDS) for that specific color. Don't rely on the Q tier alone.

The rating addresses fabrication risk, not consumer risk. A finished countertop installed in a kitchen poses no silicosis risk to homeowners. The silica is locked in a resin matrix. The danger is in the dust generated during cutting, grinding, polishing, and templating—work fabricators do every day. Q ratings exist to protect those workers.

Not all Q10 products are the same. Two slabs can both carry a Q10 rating with very different compositions and performance characteristics. The Q rating tells you about silica content; it doesn't tell you everything about durability, aesthetics, or fabrication behavior.

Q10 vs Q40: What the Difference Actually Means

If you're a fabricator deciding what to stock, or a distributor advising clients on compliance, here's the practical comparison.

Dust Generation

When you cut a Q40 slab with wet tooling, you generate roughly one-third the respirable crystalline silica dust of a traditional 90% quartz slab. Meaningful reduction. Not trivial. But not the same as Q10.

When you cut a Q10 slab with proper wet-cutting and vacuum controls, the RCS generated drops to roughly one-tenth of traditional quartz. In shops running full water-fed systems with HEPA-filtered extraction, Q10 fabrication can be reliably managed below OSHA's permissible exposure limit (PEL) of 50 µg/m³.

For larger, well-equipped fabrication operations: Q40 is likely manageable with rigorous controls. For smaller shops with less robust engineering controls, Q10 gives substantially more safety margin.

Price

Low-silica products carry a 10–15% price premium over comparable traditional quartz. Recycled glass costs more to source and process than mined quartz. Advanced binder systems add cost. R&D gets priced in.

Q10 products tend to sit at the higher end of that premium. Q40 products—Caesarstone Mineral and NeoQ in particular—often land closer to the traditional quartz price band, making the compliance upgrade more accessible for distributors watching margin.

Aesthetics

This is where early adoption was rocky. Replacing 80% of a slab's silica content affects how light moves through the material, how veining reads at the edge, and how the surface polishes. The first generation of low-silica products looked noticeably different—not bad, but different.

Manufacturers have largely closed that gap. Silestone XM uses Inlayr technology (introduced in 2025/26) to achieve full-depth through-veining that holds up at edges and miters. Caesarstone Mineral preserves its marble-look legacy designs. Aurea PHI uses a proprietary printing process engineered specifically for realistic marble movement. Current Q10 and Q40 products look like premium quartz in finished installations.

Fabrication Behavior

Fabricators in reddit.com (r/Countertops) report that low-silica slabs behave similarly to traditional quartz—same diamond blades, same CNC equipment, same polishing pads. Some products show slightly higher heat sensitivity due to recycled glass content, which requires attention to feed rates. Blade wear is comparable. Dust settles faster during wet cutting, which is a job site improvement most fabricators notice immediately.

The transition for most shops has been less disruptive than anticipated.

The Four Key Low-Silica Products in North America

Silestone XM (Q10) — Cosentino

Silestone XM is the product that defined the Q10 category in North America. Cosentino made a full commitment: 100% of Silestone production transitioned to low-silica formulations.

• Silica content: Strictly less than 10% crystalline silica

• Technology: Hybriq+® — a mineral blend with a minimum of 20% recycled glass and porcelain

• Performance: N-Boost liquid repellency maintained; high scratch resistance

• Sustainability: Manufactured using 99% recycled water and 100% renewable energy

• New for 2025/26: Inlayr technology delivers full-depth through-veining, solving the edge-look problem that plagued earlier low-silica products

• Distribution: The most widely available Q10 product in North America by a wide margin

Who it's right for: Fabricators and distributors who need consistent Q10 availability, proven performance, and broad color selection. If you need Q10 and you need it reliably in stock, Silestone XM is the default answer.

Caesarstone Mineral™ (Q40, select colors near Q10) — Caesarstone

Caesarstone rebranded its core North American line to Mineral™ Surfaces—a deliberate signal about where the product is heading.

• Silica content: Maximum 40% (Q40), with some colors approaching 10%

• Composition: Quartz replaced with albite (feldspar) and recycled glass

• Certifications: NSF-certified for food contact, non-porous, mold resistant

• Format advantage: Jumbo slabs (131.5" × 64.5") reduce seams—a meaningful spec for large kitchens and commercial work

• Marketing position: "The Art of Mineral" — heavy emphasis on design continuity with traditional quartz aesthetics

One thing to know: Caesarstone also offers the ICON™ collection at less than 1% silica, in Q-Zero territory. If silica level is a hard requirement in your spec, clarify which product line you're ordering. Mineral™ and ICON™ are very different products.

Who it's right for: Distributors with existing Caesarstone relationships who need Q40 compliance at familiar price points, and fabricators comfortable managing Q40 exposure with proper controls.

Viatera NeoQ™ (Q40) — LX Hausys

LX Hausys (formerly LG Hausys) manufactures NeoQ slabs in Georgia, USA. Domestic production is a meaningful differentiator for commercial projects with Buy American requirements or LEED points dependent on manufacturing origin.

• Silica content: Under the Q40 threshold

• Composition: High post-industrial recycled glass and minerals; TrueView digital printing for surface aesthetics

• Certifications: Greenguard Gold certified for indoor air quality; VOC-free

• Fabrication: Works with standard quartz tooling

• Market focus: Green building and LEED-driven commercial projects

Who it's right for: Commercial specifiers who need Greenguard Gold documentation, domestic manufacturing, and recycled content verification. The sustainability story is legitimate and backed by third-party certification.

Aurea Stone PHI & Symphony Lines (15–20%) — Aurea Stone

Aurea Stone occupies an interesting position: their PHI line sits at 15–20% silica—technically Q40, but substantially below the ceiling. The brand built its reputation on realistic marble movement well before low-silica became a regulatory requirement.

• Silica content: Approximately 15–20%

• Technology: Proprietary "4R" formula; advanced digital printing for deep veining

• Physical properties: Exceptionally dense; superior moisture resistance

• Binders: Eco-resin systems

• Context: Aurea has since launched the ZERO line at 0% silica, so the full portfolio now spans 15–20% (PHI/Symphony) down to true zero (ZERO)

Who it's right for: Projects where maximum visual realism in marble aesthetics is the primary driver and you're evaluating within the Q40 tier. Worth specifying by name if the aesthetic is what's selling the client.

Notable Mentions: Other Low-Silica Products Worth Knowing

The four brands above are the ones you'll encounter most in North American distribution. But the low-silica category is broader, and a few other products are worth knowing—particularly for commercial projects, international sourcing, or clients pushing into more specialized spec territory.

Neolith (Q9) — TheSize

Technically sintered stone rather than engineered stone, Neolith sits below 9% crystalline silica and qualifies as Q10-equivalent. The sintering process—compressing and firing minerals at extreme heat—produces a surface that's UV-stable, suitable for outdoor applications, and extremely hard. If a project needs low-silica performance on an exterior countertop, cladding, or outdoor kitchen surface, Neolith is one of the few products that handles it.

• Silica content: Below 9% (Q10-equivalent)

• Format: Available in large-format slabs for cladding and flooring in addition to countertops

• Differentiator: UV stability and outdoor suitability set it apart from resin-bound engineered stone

Compac Obsidiana (< 7%) — Compac Surfaces

Made from 100% recycled glass, Obsidiana sits below 7% silica—well inside Q10 territory, and approaching Q-Zero in some formulations. It occupies a hybrid positioning: the recycled glass content aligns it with the silica-free alternatives category in terms of composition, but it fabricates like engineered stone.

• Silica content: Less than 7% crystalline silica

• Composition: 100% recycled glass binder system

• Positioning: Sits between Q10 and Q-Zero; useful for projects where recycled content documentation is required alongside low-silica compliance

HanStone — Hanwha Surfaces

HanStone is transitioning select collections within its North American portfolio toward low-silica formulations. The brand has strong commercial distribution in Canada and the U.S., and is a significant presence in the mid-market segment.

• Status: Transitional — not all collections are low-silica, so confirm product line before specifying

• Strength: Established distribution and commercial track record across North America

• Watch: New low-silica collections expected through 2026 as the transition accelerates

Stone Italiana — Cosmolite

An Italian manufacturer targeting the Q10 segment with pre-consumer recycled minerals. Cosmolite is less widely distributed in North America than the brands above, but it's worth knowing for projects with European supply chain connections or where recycled pre-consumer content is a spec requirement.

• Silica content: Very low; targeting Q10 designation

• Composition: Pre-consumer recycled minerals

• Distribution: Selective; primarily available through specialty stone distributors

How Much Silica Is Safe?

The regulatory answer in North America isn't "Q10" or "Q40." OSHA's permissible exposure limit (PEL) for respirable crystalline silica is 50 micrograms per cubic meter of air (µg/m³), averaged over an 8-hour workday. There's also an action level of 25 µg/m³, at which point enhanced controls and medical surveillance are required.

The Q rating of a product affects how easily a shop stays under those limits. A Q10 slab generates roughly one-tenth the RCS of traditional quartz during cutting. That creates meaningful compliance margin with standard wet-cutting. A Q40 slab generates more, requiring tighter practices to hit the same outcome.

The honest answer for fabricators: no silica percentage makes dry cutting without controls safe. Q10 reduces risk substantially. It doesn't eliminate it. Engineering controls—water-fed tools, HEPA vacuum extraction, enclosed cutting environments—remain required regardless of Q rating.

What Q10 buys you is margin. More margin means better compliance odds, lower worker exposure, and a stronger position if OSHA conducts an inspection.

Common Misconceptions

"Low silica quartz is silica-free."
It's not. Q10 still contains up to 10% crystalline silica. Q40 contains up to 40%. Neither qualifies as silica-free. True silica-free products—Caesarstone ICON, Aurea Stone ZERO, BioQuartz—are a separate category at below 1%.

"The Q rating protects homeowners."
It doesn't apply to homeowners at all. A finished, installed countertop poses no silicosis risk to occupants. The rating addresses fabrication safety—the risk during cutting, grinding, and polishing.

"Q40 and Q10 are equivalent for compliance purposes."
They're meaningfully different. Q10 is substantially more forgiving of imperfect engineering controls. Q40 requires tighter practices to achieve the same OSHA outcome.

"All low-silica products look inferior to traditional quartz."
Early products had this problem. Current products—Inlayr, TrueView, Aurea's 4R process—are largely indistinguishable from traditional quartz in finished installations.

"'Mineral surface' is just a marketing rebrand."
Partially true. Brands are distancing themselves from the word "quartz." But the name also reflects something real: these products have genuinely different mineral compositions. They aren't the same material with a new label.

How to Specify Low-Silica Products

A few practical notes for architects and designers:

Be specific. "Low silica quartz" is not a precise specification. Reference the brand, product line, and Q-rating tier. If the project has OSHA compliance documentation requirements or green building targets, include those requirements explicitly.

Request the SDS for specific colors. The Q rating tells you the maximum silica content. The SDS tells you the actual content for that specific color. Some Q40 products land much closer to Q10 in practice.

Pair material specs with fabrication requirements. Specifying a Q10 slab doesn't automatically ensure safe fabrication. If certified silica-safe fabrication practices are required, specify that separately or confirm practices with your fabricator before the job starts.

Check regional availability. Silestone XM has the broadest North American distribution. NeoQ is strong in commercial markets. Aurea PHI and Symphony have more selective distribution. Confirm before specifying to avoid substitution issues.

What's Next: The Move Toward Q-Zero

Q10 and Q40 are transitional standards. The direction is Q-Zero—below 1% silica, or true silica-free formulations.

Caesarstone ICON launched in 2025 and began full North American rollout in 2026. Aurea Stone ZERO is shipping. BioQuartz has achieved pyrolytic transformation that eliminates crystalline silica entirely - an innovative material that Radical Surfaces will be featuring in the future. These products eliminate the fabrication hazard at the material level, rather than managing it with engineering controls.

The Q10 and Q40 tier will remain relevant—not every manufacturer has a silica-free line, and Q-Zero products carry higher price premiums. But if you're building a distribution strategy for 2026 and beyond, knowing exactly where each product lands on this spectrum is no longer optional.

For a full comparison of silica-free alternatives—including engineered options like ICON and ZERO alongside non-engineered alternatives like IceStone, Soapstone, and PaperStone—see our complete silica-free countertop guide.

Frequently Asked Questions

What is the difference between Q10 and Q40 low silica quartz?
Q10 means the slab contains less than 10% crystalline silica. Q40 means less than 40%. Both represent significant reductions from traditional quartz (90%+). Q10 generates substantially less respirable silica dust during fabrication, making it easier to stay under OSHA's permissible exposure limit with standard wet-cutting controls. Q40 requires more rigorous engineering controls to achieve the same safety outcome.

Which brands make Q10 low silica quartz?
Silestone XM by Cosentino is the most widely available Q10 product in North America. Other products approaching Q10 levels include select colors within the Caesarstone Mineral range and Compac Obsidiana (recycled glass, under 7% silica). True Q-Zero products—Caesarstone ICON, Aurea Stone ZERO, BioQuartz—go further and eliminate silica almost entirely.

Is low silica quartz safe for homeowners?
Yes. The silica in engineered stone is locked within a resin matrix in the finished product. An installed countertop poses no silicosis risk to homeowners or occupants. The Q-rating system addresses safety for fabricators—the workers who cut, grind, and polish the material during production and installation.

How much silica is safe for countertop fabricators?
OSHA's permissible exposure limit (PEL) for respirable crystalline silica is 50 µg/m³ averaged over an 8-hour workday. The action level—where additional controls and medical surveillance kick in—is 25 µg/m³. No specific silica percentage in a slab guarantees compliance on its own; what matters is the airborne concentration at the worker's breathing zone. Q10 products generate substantially less RCS during fabrication, creating more compliance margin than Q40 or traditional quartz.

Is low silica quartz more expensive than traditional quartz?
Typically yes, by 10–15%. Q10 products like Silestone XM sit at the higher end of that premium. Q40 products like Caesarstone Mineral and NeoQ are often closer to traditional quartz pricing. The premium reflects higher input costs—recycled glass costs more to source than mined quartz—and the R&D investment in new binder and printing technologies.

Can you fabricate low silica quartz with standard tools?
Yes. Q10 and Q40 products work with standard quartz fabrication tooling—same diamond blades, CNC equipment, and polishing pads. Some products show slightly higher heat sensitivity due to recycled glass content, which requires attention to feed rates. Blade wear is comparable. Wet cutting with HEPA vacuum extraction remains required practice regardless of Q rating.

Internal links:

• OSHA Silica Regulations 2026: Complete Compliance Guide for Countertop Fabricators

• Silica-Free Countertop Options 2026: Complete Guide to Engineered Stone + Alternatives

Silica Free News is the leading independent publication covering silica-free and low-silica countertop materials. We provide in-depth reviews, comparisons, and regulatory updates for distributors, fabricators, architects, and interior designers across North America.