STEM toys
Mohs Hardness Test Kit — 10 Mineral Samples with Porcelain Streak Plate
Review
What’s included
The kit contains ten certified mineral specimens that represent the Mohs hardness scale: talc, gypsum, calcite, fluorite, apatite, orthoclase (feldspar), quartz, topaz, corundum, and a synthetic silicon carbide sample, along with one unglazed porcelain streak plate for streak and scratch testing.
Materials and presentation
Each sample is a natural mineral fragment (not polished gemstones) and is intended for hands-on testing. The synthetic silicon carbide (carborundum) serves as the high-hardness reference. The kit’s ceramic streak plate is bare (unglazed) so you can observe streak color and conduct scratch checks.
Size and storage
Specimens are compact and meant for classroom demos or field kits; they are small enough to pack into the lightweight storage case with individual compartments for each mineral. The case keeps pieces organized and portable for outdoor use or transport between lessons.
How it’s used
Use the included guide to perform scratch tests across the scale: try scratching softer samples with harder ones, check streaks on the porcelain plate, and compare physical traits against the identification card. The set is suitable for teaching mineral properties, grouping rocks by hardness, and expanding a personal collection with hands-on practice.
Pros
- Complete range of ten minerals for Mohs testing
- Portable case with individual compartments
- Includes unglazed porcelain plate and simple guide
Cons
- Specimens are relatively small
- Not gem-quality — natural fragments only
- Some samples may show labeling or hardness variation
VerdictThis kit provides a full set of samples across the Mohs scale plus a porcelain streak plate and a compact storage case, making it a solid hands-on tool for learning and basic field identification. The specimens are convenient for demonstrations and travel, and the included guide helps beginners get started. Note that the pieces are small and not gem-quality; there can be variability in sample hard
Reviews
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Julio Cesar 5/5
Small but serviceable stones
Stones are on the small side, yet they perform for basic testing and learning.
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STEVE FISHER 5/5
Good value for a starter set
Useful samples for basic hardness checks; overall I'm satisfied.
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New Home-Educator Life! 4/5
Compact but practical
Nice small kit for children to examine mineral traits. The testing tool works well, though I expected larger pieces.
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Jennifer 5/5
Fun for learners and hobbyists
Entertaining for kids and adult rock collectors. Case protects the contents. Stones are small but adequate for using the ceramic plate or slate.
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A Guy Named Courtney 3/5
Topaz seems softer than expected
Good overall, but the topaz sample tests softer than quartz — closer to a 6.5 in my checks.
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pichi 4/5
Arrived a bit late
Arrived; all OK.
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Anne in Indy 4/5
Solid option for hobby rockhounds
Covers the full scale and suits casual use. I upgraded the storage to a snap-close box and labeled compartments for neatness.
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Dr.P 2/5
Check specimen size first
Many pieces are tiny and hard to hold for those with larger hands. Might be fine for children.
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Homesteading with Birds 5/5
Handy classroom and field reference
Convenient to have the whole Mohs range in one kit. Samples fit compartments and match the ID card; the diamond sample is dark but functional.
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