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Perhaps you would like to cut agates or thunderheads, investigate the inside of a geode, slice granite or marble tiles to shape, or slice rocks into slabs for use as slate tiles or crazy paving. Whatever your particular needs, you will need a rock-cutting saw. Which is the best saw for cutting rocks? We review three.
You can cut rocks with wet tile saws or lapidary saws fitted with diamond blades. However, not all saws in these categories are equal, and there are particular features you should look for when buying a rock-cutting saw. Rock cutting saws require high RPMs and power to cut through the tough material.
Rock cutting is a specialized task, and you cannot use any old saw for the job – most handsaws and power saw blades are designed for cutting wood, and you will not be able to use them for cutting rocks. But some saws are made explicitly for cutting stones, and we will advise you precisely what to look for.
If you are interested in checking out the best saw for cutting rocks you can find it by clicking here (Amazon link).
What Kind Of Saw Is Best For Cutting Rocks?
Rocks, even relatively soft ones, are very tough, unforgiving materials to saw, and you will need a saw that is up to the task. The three main types of saw that you probably already have on hand that can serve to cut rocks are circular saws, band saws, and tile saws. In all cases, they need certain technical specifications.
The saw will require a lot of motor power and a high RPM to chew its way through tough material such as rock.
Circular saws can typically run around 4000 to 6000 RPM, which is suitable for cutting stones. Band saws are generally not as powerful but can still run over 3000 RPM. Tile saws range from 3000 to 6000 RPM.
However, it isn’t only the motor that determines whether you can cut rocks with a saw. You will also require a blade that is up to the task of slicing through such durable material, which generally means you will need a diamond-coated blade.
As diamond is the hardest substance known (rated 10 on the Mohs hardness scale), it will cut through the rocks effortlessly (provided the saw’s motor can deliver enough power).
Having said that you can use a circular saw or band saw with a diamond blade, there are specialist saws designed from the beginning to cut masonry or rock, and these are generally the better option for cutting stones.
As a diamond blade grinds its way through rock, it spits out a lot of dangerous dust and can rapidly overheat.
Specially designed stone saws (lapidary saws) generally incorporate a mechanism to release water onto the blade and stone during cutting to dampen the dust and keep the saw from overheating. Doing so also helps prolong the blade’s lifespan.
Tile saws also generally incorporate this mechanism to release water but are usually smaller and lighter, with a table that slides toward the blade. In contrast, the blade moves on stone saws to relieve the operator from lugging bulky, heavy pieces of rock.
If you can afford it, buy a specialist lapidary saw, as it has all sorts of features for improving your control when slicing and shaping rocks.
BTW: Do you want to know more about rock and mineral identification? The books listed below are the best ones you can find on the internet (Amazon links):
- Smithsonian Handbooks: Rocks & Minerals
- Gemstone & Crystal Properties (Quick Study Home)
- Ultimate Explorer Field Guide: Rocks and Minerals (National Geographic Kids)
Can A Wet Tile Saw Cut Rocks?
Wet tile saws, which resemble small table saws, miter saws, or radial arm saws, use water to cool the diamond-coated blade.
As the name indicates, they are designed for tile, but if you cannot afford a lapidary saw, you can use one as a cheaper substitute. Not only can you make straight cuts, but you can also cut angles, bevels, and small shapes.
If you are going to use a wet tile saw as a substitute for a lapidary saw, do not splash out on the professional tile saws that resemble miter saws or radial arm saws. You can pick up a used lapidary saw for the same price as one of these.
Instead, go for a basic tile saw that resembles a table saw. Check that it has a decent blade kerf and a water cooling system, which is generally a reservoir below the table.
As the blade spins through the water, it gets wet. It turns the wet rock into mud rather than rock dust, which is hazardous to your respiratory system, mainly if the rock is silica-based, as many lapidary stones are.
Wear proper respiratory protection and preferably work outside. Wear eye protection in case of flying stone chips. Wear hearing protection, as things will get loud when cutting rock.
Take steps to ensure water does not contact the electrical outlet. You may also wish to wear a leather apron to protect yourself against chips and spatter.
You will not generally have to worry about the blade cutting you – it will abrade you and cause mild burns if it contacts your skin. However, note that very thin diamond blades used on lapidary saws (in the .004 to .006 inch range) will cut fingers, and you should exercise extreme caution.
To cut stone with a tile saw, mark it using a sharpie and wet it to ensure your first cut is not dry. Place the stone on the other end of the tile saw, and gently pull it toward you along the marked line. Go slowly and do not use much pressure.
Plan your cuts carefully, and account for the blade’s kerf. Do not push the stone, as it results in more flying debris, and do not pull the rock too hard, as it risks damaging the saw through overheating and creating a rougher cut with many more chips. Never force the stone, as you risk the blade getting bound and throwing the rock.
When you have finished cutting, drain the water out of the reservoir and dry the blade to ensure it does not rust. Applying a bit of mineral oil or 3-in-1 can help in protecting your saw against corrosion.
TIP: Holes in rocks are usually a sign of rock weaknesses. Find out how holes in rocks are formed and more in the article below:
Holes in Rocks Explained: How Are Formed & What Causes Them
Will A Diamond Blade Cut Rocks?
Diamond blades, whether the cheaper diamond-coated blades with a thick kerf designed for use on tile saws, or the thinner, high-quality lapidary blades, will cut rocks. Diamond is the hardest mineral and can grind through anything softer.
Having said that diamond blades can cut rocks, let us look at this in more detail. Not all stones are equal, nor are all diamond blades identical.
The Mohs scale of mineral hardness measures the hardness of rocks. This scale is a qualitative ordinal one, where the numbers assigned to the rocks indicate how hard they are relative to each other.
Hardness is determined by the ability of a harder rock to scratch a softer one. In other words, the Mohs scale is a scale of scratch hardness.
It is an ordinal scale and does not indicate absolute hardness. Scratch hardness measures the resistance of samples to plastic deformation or fracture from friction produced by a sharp object.
Here is a table of the ten minerals that make up the Mohs scale of mineral hardness, with absolute hardness included.
| Mineral | Mohs hardness | Absolute hardness |
|---|---|---|
| Talc | 1 | 1 |
| Gypsum | 2 | 2 |
| Calcite | 3 | 14 |
| Fluorite | 4 | 21 |
| Apatite | 5 | 48 |
| Orthoclase feldspar | 6 | 72 |
| Quartz | 7 | 100 |
| Topaz | 8 | 200 |
| Corundum | 9 | 400 |
| Diamond | 10 | 1500 |
For comparison, common lapidary rocks have a Mohs hardness of 5.5. to 6 (opal), 6.5 to 7 (agate and jasper), and 6.5 to 7.5 (various varieties of garnet). Amethyst, being a variety of quartz, has a hardness of 7.
Whether going by Mohs hardness or absolute hardness, a diamond is much harder than any rock you will be cutting and can cut through it.
However, it will encounter more resistance with a harder rock such as corundum (for example, ruby or sapphire) than with feldspar or quartz-based rock. Even softer rocks will be a breeze for a diamond blade to cut.
In addition to differences between rocks in hardness, there are differences between diamond blades. Unlike heavier blades, skinny diamond blades are extremely easy to bend.
We recommend using thicker blades for most rocks and keeping the very thin blades for costly material where you do not want to lose much to the kerf.
Apart from differences in size, blades also differ in the amount of diamond on the blade, which consequently affects the price.
If you only occasionally cut, you can get away with moderately decent quality blades where the diamond abrasive is rolled or bonded onto the cutting edge. Although these will wear out sooner, they will serve if you are not using them frequently.
We recommend you avoid very inexpensive blades, which represent a false economy. Most of these blades will only cut three or four rocks so you will have wasted your money.
If you are sawing rocks frequently, we recommend using sintered blades. Sintered blades have diamonds throughout the rim instead of only bonded onto the surface. Because they contain more diamonds, these blades cost quite a bit more, but they will last considerably longer, making them a worthwhile investment.
TIP: A Mohs hardness test is one of the most useful tricks that should be in all rockhounds’ playbooks. Check out the best Mohs hardness test kits in the article below:
3 Best Mohs Scale Test Kits: Test Hardness of Your Gemstones
What To Look For When Buying Saw For Cutting Rocks
When looking for a saw to cut rocks, there are certain things you should consider before buying.
Consider the size of the samples you want to cut. Although getting a smaller saw will save you money upfront, you may be limited down the line when you wish to slice through larger rocks. Getting a bigger saw, to begin with, may be a better idea in terms of the economy.
Here is a table of saw blade diameters and the rock sizes you can cut with them. Remember that this is a guideline; you can slice slightly larger rocks with a given blade size. However, doing so will cause the blade to wear out faster.
| Saw Blade Diameter | Rock Sample Diameter |
|---|---|
| 6 to 8 inches | Up to 2 inches |
| 10 inches | Up to 3 inches |
| 12 inches | 3 to 4 inches |
| 14 inches | 3 to 5 inches |
| 16 inches | 3 to 6 inches |
| 18 inches | 3 to 7 inches |
| 20 inches | 3 to 8 inches |
| 24 inches | 3 to 10 inches |
| 30 inches | 3 to 12 inches |
| 36 inches | 3 to 15 inches |
Furthermore, look for a welded steel plate lubrication reservoir to act as a solid, stable base, strong legs, and sealed arbor bearings to exclude the slurry formed by cutting.
Ensure that the carriage can move smoothly and that there is a coolant deflector on the blade and a full steel hood for safety and to contain splashing.
Choose a saw with an accessible vise strong enough to hold irregularly-shaped samples, a cross-feed device for accurately cutting multiple slabs, and a power feed to maintain the steady, firm pressure of the sample against the blade.
Ensure that you can adjust the infeed rate to compensate for differences in size, hardness, and density between samples.
TIP: Gloves will give your fingers valuable protection when you’re working with your lapidary saw. Check out my recommendation for the best gloves in the article below:
3 Best Gloves for Rockhounding: Protect Your Hands
Best Saws For Cutting Rocks
We have combed through the numerous saws on the market for cutting rocks, and selected three of the best. Whatever your particular needs or budget, one of these saws should suit your workshop.
The Best Option
The best option for cutting rock samples is Hi-Tech Diamond’s 6-inch lapidary trim saw (Amazon link), made by a small American company in the US.
This saw is specifically designed to cut rocks and does so with excellence, thanks to its powerful 1/4 horsepower heavy-duty motor with variable speed. You can cut at anything from 800 RPM to 3400 RPM, depending on the needs of the sample.
It is made of lightweight, impact-resistant, and rust-resistant material for an exceptionally durable machine and uses a 6-inch diamond saw blade. It comes with a second blade, a spray shield, an Allen wrench for any adjustments you may need to make, and complete instructions.
With this specialist lapidary saw, not only can you make rough cuts in rocks, but you can also trim out cabochon preforms and facet material.
Check out the latest price for this lapidary saw on Amazon here (Amazon link).
The Value For Money Option
The Skil 7-inch wet tile saw (Amazon link) represents a highly affordable option. It is made of corrosion-resistant steel and features a water reservoir to cool the blade and damp down dust.
An adjustable rip fence and miter gauge allow accuracy when making straight and miter cuts, and you can bevel cuts up to 45 degrees. It features a robust cross-cutting capacity (7.75 inches) and diagonal cutting capacity (7.25 inches).
Check out the latest price for this wet tile saw on Amazon here (Amazon link).
The Best Alternative
Gryphon Corporation’s C-40 Band Saw (Amazon link) is an excellent alternative to Hi-Tech Diamond’s lapidary saw. It will handle cutting rocks with as much ease as cutting glass due to its diamond blade and high-speed motor.
Its simple construction with fewer moving parts simplifies operation and means there is less to go wrong. It employs a water reservoir that recirculates water within the saw as it cuts. Two guides, one under the table and the other above, make it a very safe saw.
Check out the latest price for this lapidary diamond blade saw on Amazon here (Amazon link).
Conclusion
You can cut rocks with a specialist lapidary saw, but try a wet tile saw for a cheaper alternative. In either case, you will need to fit a diamond blade onto them to saw through the stone.
Choose from one of the three saws we have picked out for you, and start having fun slicing rocks!
TIP: Taking the correct safety measures and knowing what tools are fit for cutting rocks is very important. Find out other possible options on how to cut rocks in the article below:
What Can I Use to Cut Rocks? These 5 Tools are the Best!