phosphates
Apatite
- Also known as
- fluorapatitehydroxylapatiteasparagus stonephosphate rock
- Crystal system
- hexagonal
- Hardness
- 5 on the Mohs scale
- Lustre
- vitreous
- Colour
- Green, blue, yellow, violet, colourless
- Where it forms
- In igneous rocks as a common accessory, in metamorphic rocks, and in enormous sedimentary phosphate deposits formed from accumulated marine organic matter.
- Chiefly from
- MoroccoFlorida, United StatesKola Peninsula, RussiaMadagascarMexico
Why it is that colour
Rare earth elements and manganese. The intense neon blue-green of Madagascan material comes from manganese, and much apatite fluoresces strongly.
Safety
Safe to handle. Phosphate rock contains naturally occurring uranium and cadmium at low levels, which is an agricultural and industrial concern rather than a specimen one.
Where it comes from
Phosphate rock is mined at a scale of well over two hundred million tonnes a year, almost entirely for fertiliser. Morocco and Western Sahara hold the majority of world reserves, and phosphate extraction in Western Sahara is contested under international law because of the territory’s disputed status. Phosphate is finite, cannot be substituted, and has no synthetic alternative.
Historical use
Apatite defines position 5 on the Mohs scale. Its structure is the framework of vertebrate bone and tooth enamel, and it is therefore the mineral that every reader of this page is partly made of.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
What is attributed to it, and since when
Named in 1786 from the Greek for to deceive, because it had been repeatedly mistaken for other minerals. It has no traditional attribution, and its modern meanings are recent.
Described, not endorsed. Dating a claim is not the same as assessing it — but an association that first appears in a book published in 1985 is not an ancient inheritance, whatever the label says. A sincere account of feeling better is compatible with the stone doing nothing — see the placebo effect.
Worth knowing
Apatite is the mineral you are built from. Bone is roughly seventy per cent by weight a poorly crystalline form of hydroxylapatite, laid down on a collagen scaffold; tooth enamel is around ninety-six per cent apatite and is the hardest tissue in the body. Fluoride works by replacing the hydroxyl group with fluorine to make fluorapatite, which is less soluble in acid — which is the entire chemistry of fluoridated water and toothpaste.
It also feeds the world. Phosphorus is one of three elements plants must have and cannot fix from air, and essentially all agricultural phosphate comes from apatite. There is no substitute and no synthetic route: unlike nitrogen, which can be pulled from the atmosphere, phosphorus has to be mined. Most of the accessible reserve is in Morocco and Western Sahara, and "peak phosphorus" is a serious if contested long-run concern.
A mineral that builds your skeleton, hardens your teeth, grows your food, sits at the exact middle of the hardness scale, and carries a name meaning "to deceive" because nobody could identify it — that is a reasonable place to close.
Identity checked against IMA-CNMNC master list, June 2025.