Understanding Diamond Burs

Grotto Gemstones – Lapidary Learning Series

Choosing the Right Diamond Bur for Your Gemstone Projects

Diamond burs are versatile tools used for shaping, grinding, smoothing and refining gemstones and crystals. When fitted to a suitable rotary hand tool, they allow you to work on small areas, create contours and gradually develop the shape of your stone.

At Grotto Gemstones and Tools Australia, we offer three main types of diamond burs: electroplated, sintered and resin diamond burs.

Each type has different characteristics and is suited to particular stages of gemstone preparation.

1. Electroplated Diamond Burs

Electroplated diamond burs feature a layer of diamond abrasive bonded to a metal surface.

They are particularly useful for initial shaping, removing small amounts of unwanted material and refining the outline of gemstones.

Best suited for:

  • Initial gemstone shaping

  • Grinding and refining edges

  • Working on small contours and detailed areas

  • Beginner lapidary projects

Grotto Gemstones electroplated burs are available in four colour-coded grades:

Colour Grade: Black Extra Coarse, Green Coarse, Blue Medium and Red Fine.

Start with the least aggressive grade that will accomplish the task, then progress towards finer abrasives as the gemstone surface improves.

Important: Electroplated burs have a surface layer of diamond abrasive. Once that layer is worn away, it cannot be restored by sharpening. An aluminium oxide sharpening stone is not recommended for dressing these burs.

Water Cooling & Safe Operation

Grotto Gemstones recommends using suitable water cooling when grinding gemstones with electroplated diamond burs. A controlled supply of water at the working area helps reduce heat, minimise airborne stone dust and wash away grinding residue.

Use light, controlled pressure and allow the diamond abrasive to do the work. Excessive pressure can damage the abrasive coating and shorten the working life of the bur.

Always wear appropriate eye protection, secure your gemstone and ensure the bur is correctly fitted to a suitable rotary tool. Keep water away from electrical components and never immerse an ordinary electric rotary hand tool in water.

Cleaning & Maintenance

After use, gently remove accumulated grinding residue, rinse where appropriate and thoroughly dry the bur before storage.

Electroplated burs should not be dressed with an aluminium oxide sharpening stone because their diamond abrasive is bonded to the surface rather than distributed throughout the working head.

 

2. Sintered Diamond Burs

Understanding Sintered Diamond Burs

Sintered diamond burs are designed for precision gemstone shaping, grinding and surface refinement.

Unlike electroplated burs, which have diamond abrasive bonded to their outer surface, sintered diamond burs contain diamond particles distributed throughout a manufactured abrasive working layer.

As the working surface gradually wears, fresh diamond particles can become exposed, helping the bur maintain its cutting ability over an extended working life.

Best Suited For

  • Shaping and refining gemstones and crystals.

  • Controlled grinding of hard gemstone materials.

  • Creating curves, contours and detailed shapes.

  • Progressive surface refinement using different grit grades.

  • Lapidary work requiring durable, consistent cutting performance.

Choosing the Right Grit

Coarser sintered diamond burs are generally used for shaping and material removal, while finer grits are suited to smoothing and preparing the gemstone surface for subsequent finishing.

Begin with the least aggressive grit suitable for your task and progress through finer grades to reduce scratches.

For the best results, select a bur appropriate to the gemstone's hardness, shape and the amount of material being removed.

Water Cooling & Safe Operation

Grotto Gemstones recommends suitable water cooling when using sintered diamond burs for gemstone grinding.

A controlled water supply at the contact area helps:

  • Reduce heat generated during grinding.

  • Limit airborne gemstone dust.

  • Remove grinding residue.

  • Reduce unnecessary wear caused by overheating.

Use gentle, consistent pressure and avoid forcing the bur against the gemstone.

Always wear appropriate eye protection, secure your gemstone and ensure the bur is correctly mounted in a suitable rotary tool.

Keep water away from electrical components and never immerse an ordinary electric rotary hand tool in water.

Cleaning & Maintenance

After use, remove accumulated grinding residue, rinse the bur where appropriate and dry it thoroughly before storage.

Sintered diamond burs may gradually become glazed or lose cutting efficiency as the working surface wears.

Where suitable for the particular bur, a Grotto Gemstones Aluminium Oxide Sharpening Stone can be used to dress the abrasive working surface and help restore cutting performance.

Always follow the bur manufacturer's dressing recommendations and avoid excessive pressure when dressing.

Store burs in a clean, dry location to protect the abrasive heads and metal shafts from damage or corrosion.

3. Resin Diamond Burs

Grotto Gemstones – Lapidary Learning Series

Understanding Resin Diamond Burs

Resin diamond burs are designed for the finer stages of gemstone shaping, smoothing and surface preparation.

Unlike electroplated and sintered diamond burs, resin diamond burs use diamond abrasive held within a resin-based bonding material.

This construction allows for a more controlled and generally less aggressive cutting action, making these burs particularly useful when refining gemstone surfaces and preparing them for final polishing.

At Grotto Gemstones and Tools Australia, our resin diamond burs complement our electroplated and sintered ranges, allowing customers to progress from initial shaping through to finer surface finishing.

Best Suited For

  • Smoothing gemstones after initial shaping.

  • Refining curves, contours and detailed areas.

  • Gradually reducing scratches left by coarser abrasives.

  • Preparing gemstone surfaces for final polishing.

  • Working on smaller or delicate gemstone projects requiring controlled material removal.

Choosing the Right Grit

Resin diamond burs are available in different abrasive grades, with each grit intended for a particular stage of surface refinement.

Coarser grades are used to reduce scratches and uneven areas left by previous grinding stages.

Medium and finer grades progressively improve the gemstone's surface, preparing it for the final polishing process.

For best results:

  • Begin with a grit suitable for the surface condition of your gemstone.

  • Progress through finer grades without skipping important stages.

  • Remove scratches from the previous grit before moving to the next.

  • Use light, consistent pressure to avoid unnecessary heat and wear.

The appropriate finishing sequence depends on the gemstone material and the grit grades available.

Water Cooling & Safe Operation

Grotto Gemstones recommends suitable water cooling when using resin diamond burs that are approved for wet operation.

A controlled supply of water at the working area can help:

  • Reduce friction and heat.

  • Suppress airborne gemstone dust.

  • Remove accumulated grinding residue.

  • Protect the resin bond from unnecessary overheating.

  • Support consistent surface refinement.

Avoid excessive pressure or prolonged contact in one position, as heat buildup can damage the resin bond and affect the bur's performance.

Always ensure the bur is correctly fitted to a suitable rotary tool and follow the manufacturer's operating instructions.

Keep water away from electrical components and never immerse an ordinary electric rotary hand tool in water.

Respiratory Protection & Silicosis Awareness

Grinding gemstones can produce fine airborne particles, including respirable crystalline silica when working with silica-containing materials.

Breathing in respirable crystalline silica can cause serious lung diseases, including silicosis.

Important precautions:

  • Use effective wet-working methods and other suitable dust controls.

  • Avoid uncontrolled dry grinding of silica-containing gemstones.

  • Wear an appropriately selected and properly fitted particulate respirator when required by the exposure risk assessment.

  • Remember that water cooling reduces dust generation but does not guarantee that airborne exposure has been eliminated.

  • Keep the workspace clean using suitable wet-cleaning methods or appropriate dust extraction.

Ordinary disposable dust masks and surgical masks should not be assumed to provide adequate respiratory protection for hazardous gemstone dust.

Cleaning & Maintenance

After use, gently remove accumulated grinding residue and rinse the bur where permitted by the manufacturer's instructions.

Dry the bur thoroughly before storage, paying particular attention to the metal shaft.

Avoid dropping the bur or applying excessive pressure that could damage the resin working surface.

Where appropriate for the specific resin-bonded bur, a Grotto Gemstones Aluminium Oxide Sharpening Stone may be used to dress the abrasive surface and help maintain cutting performance.

Only dress resin burs when the manufacturer confirms that the method is suitable. Incorrect dressing can damage the resin bond.

Store resin diamond burs in a clean, dry location away from excessive heat and direct sunlight.

Grotto Gemstones Tip

For an effective gemstone finishing process, use electroplated or sintered diamond burs for initial shaping where appropriate, followed by progressively finer resin diamond burs for surface refinement.

Once the gemstone is suitably prepared, move to an appropriate polishing compound and polishing accessory selected for the particular gemstone.

Remember: Good polishing results begin with careful preparation. Scratches left behind during grinding and sanding can remain visible after final polishing.

Water Cooling, Respiratory Protection & Essential Safety

Grotto Gemstones – Lapidary Learning Series

Working safely is an essential part of gemstone cutting, shaping and polishing. Whether using electroplated, sintered or resin diamond burs, understanding water cooling, dust control and equipment safety will help protect both the operator and their tools.

1. The Importance of Water Cooling

Grinding gemstones generates friction and heat. Suitable water cooling helps control temperature, remove grinding residue and reduce the amount of dust released into the air.

When using diamond burs approved for wet operation:

  • Apply a controlled supply of water directly to the grinding area.

  • Keep the working surface adequately cooled during use.

  • Use gentle, consistent pressure rather than forcing the bur against the gemstone.

  • Avoid allowing grinding residue to accumulate around the working area.

  • Clean and dry equipment appropriately after use.

Important: Water must be kept away from electrical components. Use only rotary tools and cooling arrangements suitable for the intended wet-working application. Never immerse an ordinary electric rotary hand tool in water.

2. Understanding Silicosis and Gemstone Dust

Many gemstones and rocks contain crystalline silica, including quartz, agate, jasper and some opal-bearing materials.

Grinding these materials can release extremely fine particles known as respirable crystalline silica.

These particles may be small enough to enter deep into the lungs when inhaled.

Repeated or sufficiently intense exposure can cause serious health problems, including:

  • Silicosis: Permanent lung damage and scarring.

  • Lung cancer: An increased risk associated with respirable crystalline silica exposure.

  • Chronic obstructive pulmonary disease (COPD): Long-term breathing difficulties.

  • Kidney disease: Another recognised health risk associated with silica exposure.

Silicosis can develop over time, and severe exposure may cause disease more rapidly.

There is no cure for silicosis. Prevention is essential.

3. Wearing Suitable Respiratory Protection

Grotto Gemstones strongly encourages customers to assess respiratory hazards before cutting, grinding or polishing gemstones.

Where respiratory protection is required, use a properly selected and fitted respirator suitable for the airborne hazard.

A certified P2 particulate respirator may be suitable for some lapidary activities, but higher levels of protection may be necessary depending on exposure conditions.

Remember:

  • Surgical masks and ordinary nuisance-dust masks are not suitable substitutes for correctly selected respiratory protection.

  • A respirator must seal properly against the face.

  • Facial hair can interfere with the protective seal.

  • Follow the manufacturer's instructions for fitting, maintenance and replacement.

  • Respiratory protection should supplement effective dust controls, not replace them.

4. Keeping Your Workspace Safe

A well-organised lapidary workspace helps reduce unnecessary risks.

Before beginning work:

  • Wear suitable safety glasses or eye protection.

  • Secure gemstones appropriately before grinding.

  • Check that burs are undamaged and correctly mounted.

  • Follow the tool and bur manufacturers' operating-speed requirements.

  • Keep loose clothing, jewellery and long hair away from rotating equipment.

  • Use appropriate wet-working methods and local dust extraction where required.

  • Keep electrical connections protected from water and grinding slurry.

  • Avoid dry sweeping or using compressed air to clean gemstone dust.

  • Collect and dispose of grinding slurry carefully, preventing it from drying and becoming airborne.

Never assume that a small gemstone or a short grinding session presents no dust hazard.

5. Caring for Your Diamond Burs

Proper maintenance can help preserve cutting performance and extend the useful life of your tools.

Electroplated Diamond Burs

Gently clean and dry after use. Do not dress with an aluminium oxide sharpening stone, as the diamond abrasive is bonded to the outer surface.

Sintered Diamond Burs

Clean and dry after use. Where approved for the particular bur, a Grotto Gemstones Aluminium Oxide Sharpening Stone may be used to dress the working surface.

Resin Diamond Burs

Clean carefully, avoid excessive heat and pressure, and store away from high temperatures. Use an aluminium oxide dressing stone only where the manufacturer confirms it is suitable for the particular resin bond.

6. Further Australian Safety Information

For additional information about crystalline silica, respiratory protection and safe work practices, consult official Australian workplace safety resources:

Safe Work Australia
www.safeworkaustralia.gov.au

Workplace Health and Safety Queensland
www.worksafe.qld.gov.au

These resources provide further information about managing silica dust exposure and selecting appropriate protective measures.

 

 

A Final Word from Grotto Gemstones

At Grotto Gemstones and Tools Australia, we believe learning to shape, cut and polish gemstones should be both rewarding and safe.

Our Lapidary Learning Series has been developed to help beginners, hobbyists and experienced enthusiasts better understand their tools, improve their techniques and make informed equipment choices.

Whether you're working with your first gemstone or developing more advanced lapidary skills, remember that patience, careful preparation and safe working practices are essential to achieving beautiful results.

Learn with confidence. Work with care. Create something remarkable.

Grotto Gemstones and Tools Australia

Educational guidance only. Always follow the instructions supplied by your equipment and abrasive manufacturers and applicable Australian safety requirements.