Granite Slab Grades Explained: Commercial, Standard and Premium for Distributors

Two granite slabs can have the same name and still look worlds apart. One has an even base colour, a deep shine and clean edges. The other has small holes, filled cracks and patchy shade. Both are granite. But they sit in different grades, and they suit very different buyers.

If you sell stone in Mauritius, knowing granite slab grades is one of the best ways to guard your profit and avoid fights with buyers. Sell a top slab into a low budget job and you lose the deal on price. Sell a low grade slab into a luxury villa and the buyer may send it back. This guide shows how commercial, standard and premium grades differ, how to check them, and which grade sells best in each part of the market.

What Are Granite Slab Grades?

Granite comes out of the quarry in huge blocks. These blocks are cut into slabs, then polished or given another finish. No two blocks are the same. Some parts of a quarry give clean, even stone. Other parts have more veins, shade shifts, spots or fine cracks.

After cutting, slabs are sorted by how they look and how well they were made. That sorting is what the trade calls grading.

Keep one thing in mind from the start. There is no single world rule for commercial, standard and premium granite. Each quarry, plant and seller sets its own rules. A slab one seller calls premium may be close to another seller’s standard grade. That is why smart buyers judge slabs on clear points they can check, not on the label alone.

You may also hear other names for the same idea. Some say first, second and third choice. Others say A, B and C grade. In most markets, these line up with premium, standard and commercial.

Granite Slab Grades Comparison Table

The table shows how the three grades most often compare. Exact limits change from one supplier and one stone to the next, so use this as a guide.

Commercial Grade Granite

Commercial grade is the entry level of the market. It is still real granite, just as hard and strong as the top grades. The gap is mostly in looks. These slabs come from parts of the block with more marks, or they show more signs of the cutting and polishing work.

What to expect

• Clear shade changes, at times within one slab
• Small holes on the polished face, most of all in coarse grain stone
• Fine cracks that have been filled with resin
• Smaller slabs, so long tops need more joins
• A shine that may look patchy in direct light

Where it sells

Commercial grade sells well where price comes first. In Mauritius, that means low cost homes, rental flats, staff housing, back rooms in hotels and cafes, and small cut pieces. Think window sills, steps, skirting and small bathroom tops. When the stone is cut small, most marks drop out of sight, and buyers are glad of the low price.

The main risk is what the buyer expects. Always show the real slab or clear photos before the sale. Call it commercial grade in plain words. Most fights start when a buyer expects top looks at a low price.

Standard Grade Granite

Standard grade is the backbone of most granite trade. It strikes a good balance of price and looks. It is what most home owners picture when they think of a granite kitchen.

What to expect

• Good colour match within a bundle, with mild shade change
• Small marks in a few spots, often near the edges
• Light resin to make the face stronger and the colour richer
• A smooth, even shine
• Slab sizes that fit most kitchen plans

Where it sells

Standard grade is the best seller for kitchen tops, bathroom tops, stairs and indoor floors. It suits home owners, stone workshops, builders and mid range flat and town house projects. For most sellers, this grade should make up the largest part of the stock, since it serves the widest range of buyers.

Premium Grade Granite

Premium grade is picked from the best part of the block and handled with extra care. Buyers who notice every small detail, and who are glad to pay for it, choose this grade.

What to expect

• Very even base colour and pattern across the bundle
• Very few holes, spots or fine cracks
• A deep, mirror shine
• Tight, even thickness, which makes cutting and fitting easier
• Large slabs for long islands and tops with fewer joins
• Clean, square edges with few chips

Where it sells

Premium grade fits luxury villas, beach homes, hotel lobbies and suites, high end restaurants and smart offices. It also suits jobs where a designer has set strict rules. It is the right pick for dark stone such as absolute black too. On a dark face, every scratch, hole or dull patch shows up under lights.

Top jobs often need a lot of slabs from the same block so they all match. Check you can get the full amount before you quote. Keep the block or bundle number on file in case the buyer orders more later.

What Decides the Grade of a Granite Slab

Whatever label a supplier uses, these are the points that truly decide the grade. Use them as your check list.

1. Colour and pattern match

Lay slabs from one bundle side by side. In premium grade, the base colour and pattern should flow evenly. In commercial grade, you may see clear patches of lighter or darker stone.

2. Fine cracks and real cracks

Fine cracks are natural lines in the stone. They are most often stable, and many are filled with resin. Real cracks are actual breaks. If a crack runs right through the slab, turn it down, no matter the grade.

3. Small holes

Coarse grain granite can lose tiny bits of stone while it is polished. This leaves small holes on the face. A few small holes are fine in commercial and standard grade. Premium slabs should show very few.

4. Resin

Most granite slabs today get a resin coat. It fills fine cracks, adds strength and makes the colour deeper. This is normal and not a sign of a poor slab. What counts is how clean the resin work is. Look out for cloudy patches, uneven spots or resin that has turned yellow.

5. Mesh on the back

Some slabs have a fibre glass mesh glued to the back for support. This is most common on stone with more fine cracks. Mesh is fine, but very heavy mesh can be a sign of a weak slab.

6. Shine

Look at the face from a low angle in good light. A top shine throws back a sharp, clear glow across the whole slab. Dull patches, swirl marks or a patchy shine point to a lower grade or rushed work.

7. Thickness

Measure each slab at a few points. Even thickness makes cutting faster and keeps joins flat. When thickness jumps around, the workshop spends more time and money on each job.

8. Size and edges

Big slabs are worth more because they mean fewer joins and less waste. Check the corners and edges for chips that cut down the usable area.

9. Rust spots

Some granite holds iron in it. Over time, this can leave rust coloured spots, most of all outdoors or in wet areas. Ask how the stone has held up in wet and seaside jobs before.

Gangsaw Slabs vs Cutter Slabs

People often mix up grade and slab size, but they are not the same thing. Two main sizes are sold:

• Gangsaw slabs: large slabs cut from full blocks on big saws. They are used for kitchen tops, islands and wide floors where size counts.
• Cutter slabs: smaller slabs, most often with a fixed width, cut from small blocks. They are well liked for steps, floors, sills and low cost work.

Both sizes can come in any grade. A seller might keep premium gangsaw slabs for luxury kitchens and commercial grade cutter slabs for stairs in low cost housing.

Which Granite Grade Sells Where in Mauritius

Matching the grade to the buyer is how you win repeat orders. Here is a quick guide.

How to Build a Smart Granite Stock

Keeping every grade in every colour locks up too much cash. Most good sellers follow a simple plan:

1. Make standard grade your core. Stock the top colours, most often blacks, greys and plain tones, in standard grade.
2. Keep premium in best sellers only. Hold premium stock in two or three proven colours. Order other premium stone only when a job is confirmed.
3. Use commercial grade for bulk. It suits bulk buyers and small cut pieces, so stock it in colours that sell fast.
4. Keep bundles together. Sell slabs from one bundle to one job so the colour matches.
5. Label each bundle. Mark the grade, stone name, bundle number and thickness so nothing gets mixed up in the yard.

If your buyers also ask about other tops and floors, look at our marble range and the full stone collection for more options.

How Grade Affects Price

The price gap comes from how much good stone each block gives. A block yields only a small share of premium slabs, so those slabs cost more. Extra time spent on shine and finish adds cost too. Commercial grade costs less because more of the block makes the cut and less sorting is needed.

Colour matters a lot as well. A rare stone in commercial grade can still cost more than a common stone in premium grade. When you compare quotes, always compare the same stone, thickness, finish and grade.

Common Mistakes With Granite Grades

• Buying on the label alone: one seller’s premium may be another’s standard. Always check the slabs.
• Mixing bundles on one job: slabs from different blocks rarely match well.
• Over selling commercial grade: the wrong promise causes most complaints.
• Not checking thickness: uneven slabs raise cutting costs and leave uneven joins.
• Skipping photos before the slabs ship: clear photos of each bundle stop most fights on arrival.

Granite Slab Grades FAQs