Our readers keep the lights on and the coffee maker working hard! As an Amazon Associate, I earn from qualifying purchases.
Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
If your bits snap, wobble, or stall halfway through sea glass, agate, or river rock, the fix is not more pressure. It is picking bits sized right for your hole, running them wet, and knowing that soft stone and hard agate need different patience levels. This guide covers the nine diamond-coated sets that jewelry makers and lapidary hobbyists actually keep reordering, ranked so you can match one to the material sitting on your bench right now.
I’m Mohammad Maruf — the founder and writer behind Gardening Beyond. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Wet drilling and gentle pressure are what separate a clean hole from a shattered pendant, and matching bit diameter to your wire gauge matters more than brand. The right diamond drill bits for stone jewelry should fit your rotary tool, your material, and your patience level.
Our Picks at a Glance
How To Choose The Best Diamond Drill Bits for Stone Jewelry
Three things decide whether your bit survives the job: the hole size you need, how the bit grips your tool, and how hard the stone is. Get those right and almost any diamond-coated set on this list will finish the pendant.
Match the Cutting Diameter to Your Wire
The cutting diameter is simply the width of hole the bit creates. If you thread 18-gauge wire through a pendant, you want a bit close to that hole size. A 1.5mm bit is the standard for delicate sea glass pendants and small beads. A 2mm bit gives you more room for thicker cord. A 3mm bit is what you reach for when you need a chunkier opening or you are enlarging a hole you already started.
Buying two sizes instead of one sounds fussy until you crack a piece using a bit that was too big. Smaller bits are easier to control on thin, brittle material, so many makers step up in diameter rather than trying to open the final size in one pass.
Shank Diameter Decides What Tool It Fits
The shank is the plain stem that slides into your tool’s chuck or collet. A 1/8-inch shank fits most rotary tools and flex shafts without an adapter, which is why it shows up on so many hobby sets. A 3/32-inch shank (about 2.35mm) is the Proxxon standard and needs a matching collet. Some sets ship with collets included — that saves you hunting for the right one mid-project.
Water Cooling and Light Pressure
Diamond-coated bits grind rather than cut, so friction heat builds fast and kills the coating. Keep the tip submerged or drip water on it the whole time. Start the bit at an angle of roughly 45 degrees to bite the surface, then straighten to vertical once you have a groove. Press just enough to feel the grit working — pushing hard cracks thin glass and bends thin shanks.
Quick Comparison
| Model | Best For | Cutting Diameter | Pieces | Shank Type | Amazon |
|---|---|---|---|---|---|
| Diamond Dremel Bits 30-Pc Set★ Best Overall | All-round stone and sea glass work | 3 millimeters | 30 | 1/8 in | Amazon |
| Drilax 20 Pc 1.5mm Diamond Drill Bit SetTop Performer | Fine detailing and delicate materials | 1.5 millimeters | 20 | Round | Amazon |
| SI FANG Diamond Drill Bits 30-PcBest for Hard Stone | Hobbyists drilling multiple materials | 1 mm, 2 mm, 3 mm | 30 | Round | Amazon |
| Proxxon 28 255 Diamond Twist Drill Bits | Cleaning out holes in coral and turquoise | 0.8 mm and 1.2 mm | 2 | 3/32 in | Amazon |
| 2.5mm Diamond Drill Bit 10 Pack | Sea glass artists going through lots of holes | 2.5 millimeters | 10 | Straight | Amazon |
| 2.0mm Diamond Drill Bit 10 Pack | Hard gemstones and agate | 2 millimeters | 10 | Straight | Amazon |
| 1.5mm Diamond Drill Bit 10 Pack | Precise 1.5mm jewelry holes | 1.5 millimeters | 10 | Straight | Amazon |
| Drilax 10-Pc Diamond Drill Bits | Small holes in shells and soft stone | 2 millimeters | 10 | Straight | Amazon |
In‑Depth Reviews
1. Diamond Dremel Bits, 30-Pc Set 2mm & 3mm for Sea Glass, Stones & Lapidary
Our pick — over 4★ from 3,500+ verified ratings; the strongest balance of quality and price.
Thirty diamond bits in two working sizes, ready to punch clean holes through agate and sea glass.
This Drilax set is the one most lapidary hobbyists end up buying first, and the math explains it: thirty pieces split evenly between 2mm and 3mm bits, plus a 3mm cutting diameter that handles the pendant holes most jewelry work calls for. The 1/8-inch shank slides straight into any rotary tool or flex shaft you already own, so there is no adapter hunt before you start. Compare that to the 1.5mm Diamond Drill Bit 10 Pack sitting further down this list — that one gives you ten bits at a 1.5mm cutting diameter, while this 30-piece set more than doubles your hole size at the top end. For mixed stone work where you might drill a 2mm sea glass drop in the morning and a 3mm bead after lunch, having both diameters in one case is the whole point.
What wins people over is straightforward: the bits function the way a diamond-coated bit should, chewing through sea glass, agate slices, gemstones, and pearls without the tip skating off the surface. The set arrives in an organizer case, and the value across thirty pieces is the reason beginners and repeat buyers both land here. Run it wet at light pressure and the coating rewards you with smooth, chip-free holes in glass and porcelain. The clever part is the technique note the maker includes — water cooling, a starting angle, and light pressure — because following it is what stretches each tip past its first few holes.
The catch is durability on hard material. Diamond coating wears, and this set is no exception — hard agate and rock will dull a tip faster than sea glass or shell will. A few buyers have opened the case to find a bent tip that slipped past quality control, so give each bit a roll on a flat surface before you mount it and swap out any that wobble. Neither issue is a reason to walk away; it is the nature of the material you are grinding into.
What makes it the default pick
- 30 pieces — 15 bits each at 2mm and 3mm — so you rarely run dry mid-project
- 1/8-inch universal shank fits Dremel, rotary tools, and flex shafts with no adapter
- Diamond coating over alloy steel handles sea glass, gemstone, shell, and rock
- Organizer case keeps sizes sorted in a studio or mobile setup
Where it asks for care
- Tips dull noticeably faster on hard agate and dense rock than on sea glass
- Occasional bent bit arrives out of the case — check straightness before mounting
- Light pressure and water are not optional; dry running kills the coating quickly
Pick it when: you want one case that covers most small-stone pendant and bead work with both a 2mm and 3mm option.
Think twice if: every hole you drill is on hard agate at high volume — a single-diameter pack with more spares may stretch further.
2. Drilax 20 Pc 1.5mm Diamond Drill Bit Set, Precision Rotary Tool Bits with Collet
The 1.5mm specialist that comes with the collet already in the box, so setup is a ten-second job.
For jewelry makers chasing a specific hole size, this is the pick. The 1.5mm cutting diameter is the standard for thin sea glass pendants and small beadwork, and the set packs twenty of them. What separates it from the tweezers-and-guesswork approach is the included collet — that matching collar lets the round shank seat securely in rotary tools, flex shafts, and compatible drills without you ordering anything extra. A split point tip with diamond coating reduces the walking you get when a bit skates across a polished surface, and a 135-degree cutting angle bites consistently at the start of a hole. If your projects are all small and delicate — beadwork, tiny shells, fused glass drops — this is the diameter you want repeated twenty times.
Owners drilling glass and shells for jewelry lean on these and keep buying them, and the quality of the bits is the reason the set holds up over repeat sessions. The trade-off is the tip itself. These are small bits, and small bits break under sideways pressure — one buyer’s honest note is that you need soft pressure, especially on the smaller ones. The other piece of honest feedback is that some users find the fit with certain Dremel models less snug than expected, even though many others report a clean handshake. Check the collet seating before you commit to a long drilling run.
Speed matters more than most people realize here. Reviewers get the cleanest holes at 80-1200 RPM with the workpiece fully submerged and almost no downward pressure. Follow that and the bits reward you with straight, smooth holes; rush it and the smaller tips will fracture. It is a set that wants a light hand and pays you back for one.
Best for delicate work: if your material list is sea glass, shells, fused glass, and small stones, the 1.5mm diameter here is precisely the size you need for pinch bails and thin wire, and having twenty spares means a broken tip never stops the session.
Reach for it if: your jewelry work is all fine, small-diameter holes and you want the collet included rather than sourced separately.
Skip past it if: your pendants need 2mm-plus openings or you are drilling dense agate — this diameter is built for delicacy, not bulk removal.
3. SI FANG Diamond Drill Bits for Stone Glass, 1/2/3mm, 1/8″ Shank Fits Dremel
Ten bits at each of 1mm, 2mm, and 3mm — three hole sizes in one case for under thirty dollars.
Where the 30-piece Drilax set gives you two diameters, this SI FANG set gives you three: ten bits each at 1mm, 2mm, and 3mm. That trio maps neatly onto real jewelry work — the 1mm for the most delicate materials where standard bits just crack or wander, the 2mm for the everyday pendant hole, and the 3mm for enlarging a hole you already started. All thirty share a 1/8-inch shank with a tolerance the maker lists at ±0.02 mm, so they seat in Dremel grinders and most rotary tools without an adapter. The manufacturer also lists straightness of ≤ 0.05 mm for the bits, which is the spec that keeps a hole from drifting off-center as you drill.
The set is aimed squarely at hobbyists drilling multiple materials — sea glass, stained glass, soft stone, ceramics, porcelain, resin, quartz, and shell all appear on the maker’s list. If you want a single case that covers a mixed-material bench without buying three separate packs, this is the value play.
One important thing to flag: a couple of experienced users note these bits have flat heads and function more like grinding or etching tools than pointed drills, so if you are expecting a sharp-tipped boring bit, adjust your expectation and start with a smaller size, then step up. The maker recommends the 45-degree start growing to 90 degrees with no hard pushing, and reviewers drilling fused glass confirm that sequence produces clean, crack-free holes. For repeated heavy production drilling, look elsewhere — this set is built for one-off and small-batch projects.
Why the three-size setup wins
- 10 bits each at 1mm, 2mm, and 3mm — the full range of common jewelry hole sizes
- 1/8-inch shank seats in Dremel grinders and standard rotary tools without an adapter
- Flat-head burr design works like a grinding tool, which is actually gentler on brittle materials
- Slotted plastic case with usage instructions keeps everything sorted
Set your expectations here
- Not a traditional pointed drill bit — the flat heads grind and enlarge rather than bore straight down
- Best for one-time and small-batch projects, not high-volume production drilling
- Wet drilling is mandatory; dry running wears the diamond coating fast
Buy it for: a mixed-material hobby bench that needs 1mm, 2mm, and 3mm options all in one case.
Look elsewhere for: high-volume production drilling where you want sharp-pointed bits that will bore, rather than grind, through stone.
4. Proxxon 28 255 Diamond Twist Drill Bits 2 Pack
Two German-made diamond twist drills for clearing tiny holes in coral, turquoise, and pearl.
This is a two-piece set for a specific job: cleaning out and opening tiny bore holes in coral, turquoise, pearl, and other precious stones that already have a passage started. The bits are 0.8mm and 1.2mm, made in Germany with natural diamond dust for the cutting surface, and the twist design is meant for reaming existing small holes rather than boring fresh ones in solid rock. The 3/32-inch (2.35mm) shank is the Proxxon standard, so it fits Proxxon tools and any rotary tool with the matching collet — this is not the 1/8-inch universal fit that dominates the hobby market.
The strength here is precision on hard, valuable material. A fine tip that slips through a pearl or a piece of turquoise without shattering the surrounding surface is worth paying more per bit for, and the German manufacturer’s precision is the marketing point on the tin. If you are cleaning bezel holes, stringing pearls, or opening passages in soft-stone carvings, these tiny diameters are the ones that work.
What you need to know before buying is that this is a two-bit set at a premium-tier price, and the small tip is genuinely fragile — feedback includes a tip snapping on first use. The larger of the two bits stands up better to the job. For drilling glass specifically, this set gets mixed word of mouth from buyers who expected more from it. Use water to keep the tip cool and to avoid inhaling stone dust — the underwater drilling method works well on small crystals.
Niche but valuable: there is no other set on this list built around sub-1.5mm hole clean-out, and for pearl stringing or bezel adjustment that is exactly what you need.
Best matched with: a Proxxon tool or any rotary setup with a 3/32-inch collet, for cleaning out holes in coral, pearl, and turquoise rather than boring fresh holes.
The honest limit: it is only two bits, the smaller diameter is delicate, and the shank will not fit a standard 1/8-inch Dremel without the right collet.
5. 2.5mm Diamond Drill Bit – 10 Pack (Made in USA)
Lasco’s 2.5mm workhorse for sea-glass artists who measure projects in hundreds of holes.
Sea glass artists burn through bits, and this Lasco 10-pack exists for exactly that reality. Each bit cuts a 2.5mm hole — the middle ground between the delicate 1.5mm and the chunky 3mm — with a straight shank, stainless steel body, and 100% diamond coating. The bits are made in the USA by Lasco Diamond Products, and the price per bit lands friendly enough to treat each one as a consumable rather than a precious tool. Running them on a drill press with a water bath, reviewers report getting tens of holes out of a single bit before it dulls.
What makes this set distinctive is the durability on softer materials. Drilling ribbed glass, sea glass, pottery, ivory, and soft stone is where these Lasco bits shine — one reviewer noted 80-plus sea glass pieces on a single bit before needing a replacement. That stamina on soft, brittle stock is the reason stained-glass hobbyists keep reordering them. The straight shank works with the same rotary tools and presses you already have, and the 135-degree cutting angle is a familiar geometry that most hobbyists know how to run.
The recurring gripe is bending rather than dulling. A few buyers have pulled a bit out of the tube with a slight curve in the shank, so it is worth rolling each bit on a flat surface before you mount it — a bent bit will drill a sloppy, off-center hole. And on hard agate specifically, these softer-made bits do not hold up as well as they do on sea glass, so if your whole bench is hard stone, look at the 2.0mm or 3mm options instead.
Built for repeat sea-glass sessions
- 2.5mm cutting diameter sits between delicate 1.5mm and bulk-removal 3mm
- Stainless steel shank with 100% diamond coating, made in the USA
- Consumable-friendly pricing per bit for high-volume drilling sessions
- Straight shank works with rotary tools, drill presses, and flex shafts
Benders, not dullers
- Occasional bent bit arrives in the tube — roll each one flat before mounting
- Hard agate and dense stone dull these faster than soft sea glass does
- Small holes only — 2.5mm is fixed and cannot be widened without a second bit
Choose this if: your project list is sea glass, pottery shards, and soft stone and you want bits that endurance-test on volume work rather than on hard agate.
Consider alternatives if: every piece you drill is hard agate or dense river rock — a coarser diamond bit designed for that material will hold up better.
6. 2.0mm Diamond Drill Bit – 10 Pack (Made in USA)
A stainless-shanked Lasco bit that chews through agate and hard gemstone where softer bits stall.
Where the 2.5mm Lasco set is built for soft sea glass, this 2.0mm version is built for the harder stuff. Same maker, same USA production, same stainless steel shank with a diamond coating — but sized to a 2mm cutting diameter that suits dense gemstones, agate slices, and hard river rock. If your bench leans toward hard material rather than sea glass, this is the Lasco bit that keeps cutting after the softer options dull.
Buyers report 30-plus holes through hard agate and gemstone on one bit, submerged in water, outlasting budget coated bits. A stained-glass artist running one tube on the drill press reported a single bit lasting a full month of heavy use. One user counted 50 holes on a single bit and reordered immediately. Run it with ice water and the drill-pause-drill cadence and the coating rewards you with consistent clean holes.
The honest note: not every buyer gets that performance. One buyer mentioned a bit that did not drill glass well at all, and questions the made-in-USA claim on the pack. Given how consistent the reviews are across the rest of the set, that reads more like an outlier unit than a pattern — but it is worth buying from the listing that lets you return easily. Stick to water cooling and short bursts and the strip holds up.
Where it shines: hard gemstones, agate, and river rock — the material class where softer diamond bits give up. The stainless steel shank with 100% diamond coating holds up under the water-cooled, drill-pause rhythm that hard-stone work demands.
What to watch: a rare unit arrives underperforming, so order with an easy return path and check each bit before you commit it to a prized piece.
Reach for it if: your workbench is filled with hard gemstones, agate slices, and dense rock that softer bits will not finish.
Look elsewhere if: your materials are almost entirely sea glass and shell — the 2.5mm Lasco set covers that work more efficiently.
7. 1.5mm Diamond Drill Bit – 10 Pack (Made in USA)
Ten 1.5mm core bits that hold their edge when you keep them cool.
For 1.5mm jewelry holes — the diameter that fits a pinch bail or 18-gauge wire — this Lasco pack is the crowd-favorite among experienced lapidary artists. Ten bits, each with a stainless steel shank coated in 100% diamond with no filler abrasives, sized at a 1.5mm cutting diameter. The set performs best on a drill press, where a steadier hand than a rotary tool alone gives keeps the small bit from wandering. If you already own a Dremel press stand, this set is the natural pair.
The reason this survives repeat buying is the tip temperature. Reviewers who have tried other diamond bits say these resist the heat burnout that kills competing brands. Underwater drilling on a drill press yields roughly 20 clean 1.5mm holes per bit with no blowout on the backside. Buyers also mention fitting 18-gauge wire and pinch bails straight through.
One caveat: the set wants water and light pressure, and running it dry burns the diamond coating faster than the reviews imply. On hard stone specifically, the 1.5mm diameter is too small for bulk drilling — you want the 2mm or 2.5mm Lasco for that. And while the pack lives up to its made-in-USA claim, the general durability picture is mixed because it is limited by the small bit size itself.
Why the small size works
- 1.5mm cutting diameter fits pinch bails and 18-gauge wire cleanly
- 100% diamond coating on stainless steel shank — no filler abrasives
- Consistent 1.5mm hole size with no blowout on the backside
- Works well mounted on a drill press with the workpiece in water
Small size, small margins
- Durability is mixed — bits wear faster than expected on hard stone
- 1.5mm boring into hard agate is a slow job; the diameter is fine for sea glass but not for bulk stone
- Water cooling is not optional — dry runs shorten the coating’s life
Suits you if: your projects are sea glass pendants and bead stringing where the 1.5mm hole is the finished size and the wire fits straight through.
Not your set if: you keep reaching for agate or hard gemstone — a wider-diameter hard-stone bit is the one that will survive that work.
8. Drilax 10-Pc Diamond Drill Bits, 1.5 mm & 2 mm for Sea Glass & Jewelry
A starter set of ten 1.5mm and 2mm bits with the collets already sorted.
This Drilax pack is the low-entry option — ten bits split between 1.5mm and 2mm, plus two collets included so the bits mount directly onto a rotary tool without any extra purchase. A 135-degree cutting angle is the standard that most hobbyists know how to run, and the diamond finish is spec’d for small, precise hole work in glass, stone, and shells. If you are starting out and want to try a couple of hole sizes before committing to a bigger set, this is the low-risk way in.
The strength is small-hole versatility in brittle materials. The set is aimed at beading, pendants, sea glass, and shells — exactly the stock where a controlled hole matters more than drilling speed. Buyers find the set effective on sea shells and glass when mounted with cooling, and a couple of owners note it holds up better than similarly-priced diamond bits bought locally. That value-per-bit is what makes it worth a look for the first project.
The honest limit is durability on hard material. Diamond coating on fine small bits wears quickly — one user found they stalled out on hard fluorite, and another found them too soft for river rock. That is not a defect; it is what fine diamond bits do on dense material. If your work is soft sea glass, glass, or shell, this set is a sensible low-cost entry; if you intend to drill hard gemstone repeatedly, spend up to a set with a reinforced tip.
Fair value for the money: ten bits, two useful sizes, and the collets included gets you drilling immediately without an extra adapter order.
Watch the limits: fine diamond bits dull fast on hard material, so treat this as a soft-material starter rather than a hard-stone workhorse.
Best matched with: first-time lapidary and sea glass projects where the material is soft and the hole is small.
The honest limit: on hard fluorite and river rock these bits fall short, and the small diameter is a size you cannot widen later — plan a step-up set for harder work.
Understanding the Specs
Cutting Diameter
Cutting diameter is the width of the hole the bit will make, measured in millimeters. If you plan to thread 18-gauge wire, a 1.5mm bit gives you the snug fit; if you want room for thicker cord or beading thread, step up to a 2mm or 3mm bit. Always drill slightly larger than you need on brittle material so you have room to enlarge without cracking the piece.
Shank Type
The shank is the plain stem that mounts into your tool. The most common in hobby use is 1/8-inch round, which fits standard rotary tools, flex shafts, and Dremel collets without an adapter. A 3/32-inch shank (about 2.35mm) is used by Proxxon and needs its own collet. A straight shank works well with drill presses; a round shank suits rotary tools. Check your tool’s chuck size before you commit — the wrong shank means nothing mounts.
FAQ
Will diamond drill bits fit my Dremel rotary tool?
How do I stop diamond drill bits from breaking?
What is the difference between diamond drill bits and regular masonry bits?
Do I have to drill stone underwater?
What bit size do I need for a sea glass pendant hole?
How many holes will one diamond drill bit cut before it wears out?
Is a drill press better than hand drilling for stone jewelry?
Can I use these bits on hard agate and river rock?
How do I widen an existing hole without cracking the piece?
Should I keep the diamond bits in water during drilling?
Final Thoughts: The Verdict
For most people working stone into jewelry, the diamond drill bits for stone jewelry pick is the Diamond Dremel Bits 30-Pc Set, because thirty bits in two working sizes gives you the range to drill 2mm sea glass pendants and 3mm bead holes without reordering mid-project. If your work is fine, delicate, and all about small precise holes, the Drilax 20 Pc 1.5mm Diamond Drill Bit Set is the one to reach for, with its collet included and twenty matching diameters. And for sea glass artists who measure their week in hundreds of holes, the 2.5mm Lasco 10 Pack is built to be spent.
One honest nudge before you buy: since diamond coating wears with use on hard material, picking a set with more bits in the diameter you use most often is usually smarter than paying up for fewer, fancier tips. Match the bore size to your wire, keep the tip wet, and use almost no pressure — three habits that turn a cheap set of bits into a long run of clean, crack-free holes.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of September 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
As an Amazon Associate, Gardening Beyond earns from qualifying purchases. This does not affect which products we feature.