Is apatite durable?
Moderately. Apatite is 5 on Mohs’ scale; the fluorapatite sheet prints brittle, poor cleavage, conchoidal to uneven fracture. Gem wearability, per IGS: poor.
Moderately, and less than its hardness suggests. Apatite is 5 on Mohs’ scale, the reference step between fluorite 4 and feldspar 6, per the USGS. The fluorapatite sheet prints cleavage poor on {0001} and {10-10}, fracture conchoidal to uneven, tenacity brittle. The International Gem Society rates its wearability poor and its heat sensitivity “very”.
In short
- What the sheet prints. The Handbook of Mineralogy fluorapatite sheet: Cleavage: Poor on {0001} and {10-10}. Fracture: Conchoidal to uneven. Tenacity: Brittle. Hardness = 5. An unanalysed apatite is most probably fluorapatite, as apatite explains; the hydroxylapatite and chlorapatite sheets print the same poor cleavage and brittle tenacity, and hardness 5 and ∼5.
- Where 5 sits. USGS Gemstones: Mineral Gemstones lists the Mohs scale as talc 1, gypsum 2, calcite 3, fluorite 4, apatite 5, feldspar 6, quartz 7, topaz 8, sapphire 9 and diamond 10, and defines hardness as resistance to scratching. Apatite is itself the 5: feldspar, quartz and everything above scratch it, and fluorite and below do not.
- The poor-cleavage step. Read on their Handbook sheets by script, the ten reference minerals split by cleavage: seven print a perfect cleavage, including all four below apatite. Three do not: fluorapatite (poor), quartz (rarely observable, poor) and corundum (partings only). Apatite is the softest of those three, and the first step of the scale without a perfect cleavage.
- Documented failure: 5 is not a wearability grade. The International Gem Society apatite page gives hardness “5 (some massive varieties 3–4)”, rates wearability poor and heat sensitivity very, and says apatites don’t have the toughness of their tourmaline rivals. And the scale’s step is a group name: apatite is not an IMA species, and its three sheets print 5, 5 and ∼5.
- Not covered. This page gives no care, cleaning, storage or setting advice. Radioactivity is on is apatite radioactive, UV on is apatite fluorescent; the fluorapatite–chlorapatite comparison is on fluorapatite vs chlorapatite.
| Mohs step (USGS) | Sheet read | Hardness printed | Cleavage printed | Perfect cleavage? | Fracture printed | Tenacity printed |
|---|---|---|---|---|---|---|
| 1, talc | Talc | 1 | Perfect on {001} | Yes | Not printed | Sectile; flexible but not elastic |
| 2, gypsum | Gypsum | 1.5–2, varies with direction | {010} perfect; {100} distinct; {011} | Yes | Splintery parallel [001], conchoidal on {100} | Flexible, inelastic |
| 3, calcite | Calcite | 3 | {10-11} perfect | Yes | Conchoidal | Brittle |
| 4, fluorite | Fluorite | 4 | {111} perfect; parting on {011}, poor | Yes | Subconchoidal to uneven | Brittle |
| 5, apatite | Fluorapatite | 5 | Poor on {0001} and {10-10} | No | Conchoidal to uneven | Brittle |
| 6, feldspar | Orthoclase | 6–6.5 | Perfect on {001} and {010} | Yes | Conchoidal to uneven | Brittle |
| 7, quartz | Quartz | 7, variable by direction and form | Rarely observable, poor | No | Conchoidal | Brittle, tough when massive |
| 8, topaz | Topaz | 8 | {001} perfect | Yes | Subconchoidal to uneven | Brittle |
| 9, sapphire | Corundum | 9 | Partings on {0001} and {10-11}; no cleavage | No | Uneven to conchoidal | Brittle, tough when compact |
| 10, diamond | Diamond | 10 | {111} perfect | Yes | Conchoidal | Brittle |
| Apatite group | Hydroxylapatite | 5 | Poor on {0001} and {10-10} | No | Conchoidal | Brittle |
| Apatite group | Chlorapatite | ∼5 | Poor on {0001} and {10-10} | No | Not printed | Brittle |
Is apatite durable? What the fluorapatite sheet prints
The four fields that answer it. The Handbook of Mineralogy fluorapatite sheet reads: Cleavage: Poor on {0001} and {10-10}. Fracture: Conchoidal to uneven. Tenacity: Brittle. Hardness = 5. Durable is not a sheet term; those are the fields that stand for it. The same sheet gives prismatic hexagonal crystals elongated on [0001], to 2 m, as well as tabular, granular, globular to reniform, nodular and massive habits, and calls fluorapatite the most common rock-forming phosphate mineral.
Which apatite. Apatite is a group name. The September 2026 IMA-CNMNC Master List has fluorapatite Ca5(PO4)3F, hydroxylapatite Ca5(PO4)3(OH) and chlorapatite Ca5(PO4)3Cl, all renamed in 2010, and no plain apatite row. The hydroxylapatite sheet prints the same poor cleavage, conchoidal fracture, brittle tenacity and hardness 5; the chlorapatite sheet prints poor cleavage, brittle and hardness ∼5. The numbers agree with apatite.
Where apatite sits on Mohs’ scale
Apatite is the 5. USGS Gemstones: Mineral Gemstones says the hardness of a gemstone is its resistance to scratching and may be described relative to a standard scale of 10 minerals known as the Mohs scale, developed in 1822, and lists apatite at 5, between fluorite at 4 and feldspar at 6. So apatite is scratched by feldspar, quartz, topaz, sapphire and diamond, and scratches the four below it. The scale is a ranking of scratch resistance; the sources fetched for this page give no size for the steps between the numbers, and this page gives none.
Testing it. A hardness test leaves a mark, and how to make one where it does no harm is on how to test mineral hardness properly, not repeated here.
Does apatite cleave? The poor-cleavage step
Poorly, and that sets it apart on the scale. A script read the physical-property block of the ten sheets for the Mohs reference minerals. Seven print a perfect cleavage: talc, gypsum, calcite, fluorite, orthoclase, topaz and diamond. Three do not: fluorapatite, poor on {0001} and {10-10}; quartz, rarely observable, poor; corundum, partings only. Every reference mineral below apatite prints a perfect cleavage, so apatite is the first step of the scale without one, and the softest of the three.
Fracture and tenacity. The sheet’s fracture line, conchoidal to uneven, describes apatite’s break surfaces; reading cleavage against fracture on a specimen is on cleavage or fracture. Brittleness is the other half: 8 of the 10 reference sheets print brittle, with quartz qualified as tough when massive and corundum as tough when compact. Fluorapatite’s tenacity line is the single word brittle. The same reading for celestine, with a perfect cleavage, is on is celestite fragile.
Hardness 5 is not wearability: what the IGS records
The IGS grades its wearability lower than its hardness suggests. The International Gem Society apatite page lists apatite’s hardness as 5 (some massive varieties 3–4), its cleavage as poor, its fracture as conchoidal to uneven, its heat sensitivity as very and its wearability as poor. It writes that all gem-quality apatites have a hardness of 5 at best and that apatites don’t have the toughness of their tourmaline rivals; tourmaline is on its own page. These are the IGS’s ratings, attributed; the Handbook sheet has no wearability or heat-sensitivity field.
Documented failure: the step is a group name. The USGS writes apatite is 5, but apatite is not an IMA species, and the hardness the scale gives is a reference step, not a guarantee for any piece. The three apatite sheets print 5, 5 and ∼5, and the IGS records some massive varieties at 3 to 4. On those figures some massive apatite is softer than the scale’s step, so the 5 does not describe every specimen labelled apatite.
What this page does not cover
No care recipes. The sources quoted here describe properties; this page turns none of them into a cleaning, storage, setting or wearing method, and it does not repeat any source’s care instructions. Hazard questions go to toxic minerals in a collection, and radioactivity to is apatite radioactive and is my mineral radioactive; none of this is health or safety advice.
Related questions. UV response is on is apatite fluorescent; how fluorapatite and chlorapatite are separated is on fluorapatite vs chlorapatite. More guides are in the collecting guides. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.