Gear guide
Best coarse rock tumbler grit: 60/90 silicon carbide for step 1
Picked from Amazon listings, not hands-on tests. How we pick
Coarse grit (step 1, 60/90 silicon carbide) is the grade that runs out first. Step 1 is the only step that changes the shape of the stone, and hard, jagged rough often needs 2 to 4 one-week runs. Each run takes fresh grit, because coarse grit is spent after a week and cannot be reused. At about 2 level tablespoons per pound of rock, a 3 lb barrel takes about 4 tablespoons per run, so a kit-size packet goes quickly. The packs below are single-step coarse silicon carbide only. They differ mainly in weight (1 lb to 20 lb), in the container (jars, resealable bags, or not stated) and in grading: most are 60/90, a blend of mesh sizes, and one is a straight 60 grit. Lower mesh numbers are coarser, so 46/70 is a step coarser than 60/90 and leaves deeper scratches for step 2 to remove, while a straight 80 sits at the fine end of the 60/90 range. Nothing here was tested: every detail comes from the Amazon listings. For exact amounts per barrel, use the grit calculator on this site.
Compare the picks
| Pick | Grit | Material | Weight | Container | Price | Per lb | Link |
|---|---|---|---|---|---|---|---|
 GANGOU coarse grit 60/90, 5 lb in resealable bags | 60/90 | Silicon carbide | 5 lb | Re-closable seal bags | - | - | Amazon |
 YHAspace coarse grit 60/90, 10 lb in jars | 60/90 | Black silicon carbide | 10 lb | Re-closable jars | - | - | Amazon |
 MJR Tumblers coarse grit 60/90, 5 lb | 60/90 | Silicon carbide | 5 lb | not stated | - | - | Amazon |
 KomeStone coarse grit 60, step 1 refill, 5 lb | 60 | Silicon carbide | 5 lb | not stated | - | - | Amazon |
 MJR Tumblers coarse grit 60/90, 20 lb bulk | 60/90 | Silicon carbide | 20 lb | not stated | - | - | Amazon |
 Polly Plastics coarse grit 60/90, 2 lb (two jars) | 60/90 | Silicon carbide | 2 lb (2 x 1 lb) | Re-usable jars | - | - | Amazon |
 Fundamental Rockhound coarse grit 60/90, 1 lb | 60/90 | Silicon carbide | 1 lb | not stated | - | - | Amazon |
Facts are taken from each Amazon listing. Prices are checked daily and shown with their date.
If you just want one
- Closest match for the jobGANGOU coarse grit 60/90, 5 lb in resealable bagsThe listing states 5 pounds of 60/90 graded silicon carbide grit for the first stage (step 1).
- Most for the money on paperYHAspace coarse grit 60/90, 10 lb in jarsThe listing states 10 pounds of coarse size 60/90 silicon carbide grit for rock tumbling step 1.
- Most complete listingKomeStone coarse grit 60, step 1 refill, 5 lbThe listing states 60 grit silicon carbide for step 1 coarse grinding, in a 5 lb refill.
The picks in detail
Pick 1 · GANGOU
GANGOU coarse grit 60/90, 5 lb in resealable bags
See price on Amazon5 lb of 60/90 graded silicon carbide for step 1, packed in re-closable seal bags. A mid-size refill for a hobbyist who has to repeat the coarse step on hard rough.
What the listing offers
- The listing states 5 pounds of 60/90 graded silicon carbide grit for the first stage (step 1).
- Packaged in re-closable seal bags, which the listing says prevent spills and store unused grit.
- Listed as compatible with any brand of rock tumbler.
Limits to know
- Bags, not rigid jars: the listing does not say how many bags make up the 5 lb.
- No country of origin, usage amounts or instructions are given in the listing.
Pick 2 · YHAspace
YHAspace coarse grit 60/90, 10 lb in jars
See price on Amazon10 lb of coarse 60/90 black silicon carbide for step 1, packed in re-closable jars. A bulk pack for larger barrels or for many repeated coarse runs.
What the listing offers
- The listing states 10 pounds of coarse size 60/90 silicon carbide grit for rock tumbling step 1.
- Packaged in re-closable jars, which the listing says prevent spills and store unused grit.
- Described as graded black silicon carbide, compatible with any brand of rock tumbler.
Limits to know
- The listing does not say how many jars the 10 lb is split into.
- No country of origin and no usage amounts or instructions are given in the listing.
Pick 3 · MJR Tumblers
MJR Tumblers coarse grit 60/90, 5 lb
See price on AmazonA 5 lb pack of graded 60/90 silicon carbide for step 1 from a US-based supplier. A mid-size refill for anyone who repeats the coarse step and wants more than a jar.
What the listing offers
- The listing states 60/90 graded silicon carbide grit, the standard grading for step 1.
- Sold as a single 5 lb pack, described as the first stage grit that gives stones their initial shape.
- The listing says the company is American owned and located in Pecatonica, Illinois.
Limits to know
- The listing does not say whether the grit ships in a bag, a jar or a tub.
- The bullets are brief: no usage amounts or instructions are given in the listing.
Pick 4 · KomeStone
KomeStone coarse grit 60, step 1 refill, 5 lb
See price on AmazonA 5 lb step 1 refill of straight 60 grit silicon carbide instead of a 60/90 blend. The listing gives a usage ratio, which helps when planning how many batches a pack covers.
What the listing offers
- The listing states 60 grit silicon carbide for step 1 coarse grinding, in a 5 lb refill.
- Gives a usage ratio: about 1 oz of grit per pound of rocks, for up to approximately 80 lb of rocks.
- Listed as compatible with most standard rotary and vibratory rock tumblers.
Limits to know
- Graded as a single 60 grit, not the 60/90 blend that most step 1 instructions name.
- Container type and country of origin are not stated in the listing details used for this guide.
Pick 5 · MJR Tumblers
MJR Tumblers coarse grit 60/90, 20 lb bulk
See price on AmazonThe largest pack in this guide: 20 lb of 60/90 silicon carbide for step 1. Suits large barrels, several tumblers, or a long run of repeated coarse cycles.
What the listing offers
- The listing states 60/90 grit silicon carbide for the first stage of rock tumbling, in a 20 lb size.
- Listed as compatible with most rock tumblers, including rotary and vibratory machines.
- The listing says it can be used on stones, minerals and glass, including sea glass projects.
Limits to know
- 20 lb is far more than one small 3 lb barrel is likely to use in a short time.
- The listing does not state the container type or how the 20 lb is packed.
Pick 6 · Polly Plastics
Polly Plastics coarse grit 60/90, 2 lb (two jars)
See price on AmazonTwo 1 lb jars of coarse 60/90 silicon carbide grit for step 1. A small, tidy refill for a 3 lb barrel when a kit's coarse grit has run out before the other grades.
What the listing offers
- The listing states two 1 lb jars holding 2 lb of coarse 60/90 silicon carbide grit in total.
- Packed in re-usable jars, which the listing says prevent spills and store unused product.
- Listed as made in the USA by an American company using American sourced materials.
Limits to know
- At 2 lb in total it is a small pack for step 1, the step that is most often repeated.
- Single step only: medium grit, pre-polish and polish have to be bought separately.
Pick 7 · The Fundamental Rockhound
Fundamental Rockhound coarse grit 60/90, 1 lb
See price on AmazonOne pound of coarse 60/90 silicon carbide, listed for rotary or vibratory tumbling. The smallest pack here: a top-up when only the step 1 grit has run short.
What the listing offers
- The listing states one pound of coarse 60/90 silicon carbide grit.
- Listed as made for rock tumbling in either vibratory or rotary machines.
- The listing states that the grit is made in the USA.
Limits to know
- Only 1 lb, so it will not go far if step 1 has to be repeated on hard rough.
- The listing has three short bullets and does not describe the container.
Read before you buy
- Rock tumbling agates: grit, times and common problemsAgate tumbling schedule start to finish: grit and amount for each step, 5 to 8 weeks in total, plus fixes for pits, fractures and dull bands.
- Rock tumbling grit chart: grit size, amount and time for each stageRock tumbling grit chart for all four steps: grit size, what each step does, days per step and how to tell it is done, plus about 2 tbsp of grit per pound.
- Rock tumbler grit substitutes: what works and what failsSand, aquarium gravel, crushed glass, baking soda and no grit at all, each with a verdict. Only silicon carbide (Mohs 9 to 9.5) cuts quartz-hard rocks.
- National Geographic rock tumbler: grit amounts, times and speed settingsIndependent guide to the National Geographic rock tumbler: which grit at each step, 3 to 10 days per step, speed settings, fill level and grit amounts.
- How to make sea glass in a rock tumbler: grit, amounts and timingMake frosted sea glass in a rock tumbler: barrel 2/3 full, 2 tablespoons of coarse grit per pound, 3 to 7 days, no polish step. Recipe table and safety.
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