Is diamond a mineral?
Natural diamond is a mineral: an IMA row, C, hardness 10, density 3.511. Lab-grown diamond is not; the IMA’s 1995 definition calls it a synthetic equivalent.
Yes. Natural diamond is a mineral: the September 2026 IMA list gives it a row, formula C, grandfathered, and the Handbook sheet records it as cubic, hardness 10, density 3.511. A laboratory-grown diamond has the same structure but is not a mineral: the IMA commission’s 1995 definition calls man-made matches synthetic equivalents.
In short
- Natural diamond passes. A script over the September 2026 IMA-CNMNC Master List finds the row Diamond, C, status G, year printed as ?, country unknown. The Handbook diamond sheet gives cubic crystals, most commonly octahedral, hardness 10, density 3.511, and chemistry nearly pure carbon; the GIA diamond description puts it at typically about 99.95% carbon.
- The origin test. The IMA commission’s 1995 definition of a mineral (Nickel) says a mineral is an element or compound, normally crystalline, formed as a result of geological processes. Substances produced by people are not minerals; if identical to minerals they are synthetic equivalents. Components of meteorites and other extraterrestrial rocks count. So the answer turns on where a diamond grew, not on what it is made of.
- Five carbon rows. Counted by script (a row is a line whose first word is the name and whose formula is C), the IMA list has 5: chaoite (A, 1968, Germany), diamond (G), graphite (G, 1789), lonsdaleite (A, 1966, USA) and tartarosite (A, 2019, Germany). The Handbook’s diamond sheet names three polymorphs, chaoite, graphite and lonsdaleite; tartarosite was approved later and has no Handbook sheet.
- Lab-grown is a synthetic equivalent. Eaton-Magaña, Hardman and Odake, GIA, Summer 2024 describe HPHT growth, graphite at 5 to 6 GPa and 1300 to 1600 °C, against about 1040 to 1250 °C for natural formation, and CVD growth, a gas-phase process that bears almost no resemblance to natural formation. About 80% of the CVD-grown diamonds GIA has seen were HPHT-treated after growth.
- The type II flag, a documented limit. The same GIA paper says colourless to near-colourless laboratory-grown diamonds are type II, with no detectable nitrogen, while only about 1% of natural diamonds are. A type II result sends a stone for further testing; it does not prove it grown. Diamond simulants, which are not diamond at all, are on is zircon a diamond.
| Material | IMA row (status, year, country) | How it formed (source) | Crystal system (Handbook) | Hardness (Handbook) | Density (Handbook, measured) | A mineral under the 1995 definition? |
|---|---|---|---|---|---|---|
| Diamond, natural | C; G; ?; unknown | Kimberlite or lamproite pipes and dikes, alluvial deposits; meteorites; impact (Handbook) | Cubic | 10 | 3.511 | Yes |
| Diamond, HPHT-grown | No separate row | Graphite at 5 to 6 GPa and 1300 to 1600 °C (GIA 2024) | Same structure (GIA) | — | — | No: a synthetic equivalent |
| Diamond, CVD-grown | No separate row | Gas-phase deposition from hydrogen and methane on diamond seeds (GIA 2024) | Same structure (GIA) | — | — | No: a synthetic equivalent |
| Graphite | C; G; 1789; unknown | Metamorphism of carbonaceous sediments; igneous rocks; meteorites (Handbook) | Hexagonal | 1 to 2 | 2.09 to 2.23 | Yes |
| Lonsdaleite | C; A; 1966-044; USA | Canyon Diablo meteorite, the type locality; impact sites (Handbook) | Hexagonal | Not quoted here | Over 3.20 | Yes: extraterrestrial components count |
| Chaoite | C; A; 1968-019; Germany | Shock-metamorphosed graphite gneiss, Ries crater; meteorites (Handbook) | Hexagonal | Slightly harder than graphite | Not determined (3.43 calculated) | Yes |
| Tartarosite | C; A; 2019-016a; Germany | No Handbook sheet | No sheet | No sheet | No sheet | Yes, as an approved species |
Is diamond a mineral? The definition, applied
Natural diamond is a mineral: it is an element, crystalline, and formed by geological processes, and the IMA list gives it a row. Nickel, The definition of a mineral (Canadian Mineralogist 33, 689, 1995) sets out the definition the IMA commission adopted: in general terms, a mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological processes. Diamond on the Handbook sheet is carbon, cubic, space group Fd3m, formed primarily in pipes and less commonly dikes of deep-seated igneous origin, kimberlite or lamproite, and in the alluvial deposits weathered from them.
The IMA row. A script over the September 2026 list (pdftotext -layout; a row is a line whose first word is the name) finds Diamond, C, status G for grandfathered, the year printed as ?, the country as unknown, and Canadian Mineralogist 46 (2008) as the second reference. The list says it covers the 6239 currently valid species. The general test of what makes a mineral, worked on quartz, is on is quartz a mineral and is not repeated here.
What the sheet adds. Hardness 10; density 3.511 measured, 3.515 calculated; perfect {111} cleavage; conchoidal fracture; brittle; isotropic, n = 2.4175 at 589 nm; colourless, yellows, brown, white, blue-white, less commonly oranges, pinks, greens, blues, reds, grey to black. The name is a corruption of the Greek for invincible. The GIA diamond page says diamond forms about 100 miles beneath the surface.
Is a lab-grown diamond a mineral? The origin test
A laboratory-grown diamond is not a mineral, though it is diamond: the IMA commission’s definition excludes anything produced by people. Nickel’s text: anthropogenic substances are those produced by man, and are not regarded as minerals; if such substances are identical to minerals, they can be referred to as synthetic equivalents of the minerals in question. GIA’s Summer 2024 review describes colourless to near-colourless laboratory-grown diamonds as sharing many gemmological and physical properties with natural ones, which is the definition’s identical case.
Two routes, neither geological. GIA describes HPHT growth as subjecting a solid carbon source, typically graphite powder, to 5 to 6 GPa, equivalent to 150 to 190 km depth, at 1300 to 1600 °C, higher than the roughly 1040 to 1250 °C of natural formation, in a capsule with a diamond seed. CVD growth flows hydrogen and a hydrocarbon, typically methane, over diamond seeds while microwaves sustain a plasma: a gas-phase chemical process that, GIA says, bears almost no resemblance to natural diamond formation. GIA reports the first gem-quality laboratory-grown diamonds were HPHT-grown, though CVD was developed earlier, with the first CVD growth in 1952.
Where the answer changes. A diamond from a meteorite passes: Nickel says naturally occurring components of extraterrestrial rocks are regarded as minerals, and the Handbook sheet records diamond in carbonaceous achondrite and iron meteorites and formed by impact. Lonsdaleite, the hexagonal carbon, has its type locality in the Canyon Diablo meteorite. A diamond film grown on a tool is a synthetic equivalent whatever its purity. Meteorites themselves are on how do I know if my rock is a meteorite.
Diamond, graphite and the other carbon minerals: five IMA rows
The IMA list has 5 rows whose formula is plain C, and diamond is one. Method: every line of the September 2026 list (pdftotext -layout) whose first word is a capitalised name and whose second token is exactly C. The five: chaoite, approved as 1968-019, Germany; diamond, G; graphite, G, 1789; lonsdaleite, approved as 1966-044, USA; and tartarosite, approved as 2019-016a, Germany. Moissanite, which the list gives as SiC, G, 1905, USA (meteorite), is not carbon alone.
What the sheets record. The diamond sheet names chaoite, graphite and lonsdaleite as polymorphs; the graphite sheet names chaoite, diamond and lonsdaleite. Graphite is hexagonal, hardness 1 to 2, density 2.09 to 2.23, as on the graphite page; in water a 20.00 g piece reads 10.43 to 11.03 g against diamond’s 14.30 g. Lonsdaleite’s sheet describes very fine-grained aggregates to 0.7 mm, mixed with diamond, first found in the residue from dissolving 5 kg of the Canyon Diablo meteorite. Chaoite occurs as lamellae 3 to 15 µm wide alternating with graphite in shock-metamorphosed graphite gneiss at the Ries crater, Bavaria. Tartarosite has no Handbook sheet; this page says nothing about it beyond its IMA row.
What the count does not say. It counts rows written C. It does not say these are all the forms of carbon, or that the list is complete for carbon; it is the list as printed in September 2026.
Can you tell a natural diamond from a lab-grown one? The type II flag
Not by eye, and not by one test: GIA’s 2024 review says a type II result only narrows the question. Colourless to near-colourless laboratory-grown diamonds are type II, with no detectable nitrogen impurities, while only about 1% of natural diamonds are type II. Because laboratory-grown stones are still a small share of the diamonds submitted, GIA writes, only those that test as type II need extensive further testing. A type II stone is therefore consistent with either origin; on GIA’s statement, a colourless stone that is not type II is not one of the laboratory-grown products it describes.
A second documented limit. GIA says phosphorescence, often used as a key indicator for colourless HPHT-grown diamonds, has exceptions: a few natural type IIb diamonds and some CVD-grown diamonds react comparably. And about 80% of the CVD-grown diamonds GIA has seen were treated after growth by HPHT to improve their colour, so a stone’s history can include both processes. The identification is laboratory work; how to write the result on a label is on how to label and catalogue a mineral collection.
Not to be confused with simulants. Cubic zirconia, moissanite, zircon and glass are different materials, not diamonds of any origin; the separating numbers are on is zircon a diamond and the zircon species page, zircon.
Where natural diamond comes from
The sheet says there are numerous occurrences worldwide, but only a few of economic importance. It names the former deposits of the Golconda region and near Nágpur and Bundelkhand, India; Diamantina, Minas Gerais, Brazil (see Minas Gerais); the Orange and Vaal Rivers and the coast north into Namibia; Lunda Norte, Angola; south-eastern Sierra Leone; Kasai Province, Congo (Zaire); the Kimberley, Finsch, Premier and Venetia pipes, South Africa, where it says about 150 diamondiferous pipes have been mined; Jwaneng and Orapa, Botswana; the Mir, Udatchnaya, Zarnitsa, Aikhal and Jubileynaya pipes in Sakha, Russia; Liaoning and Shandong, China; the Argyle pipe, Western Australia; and Ekati and Diavik, Northwest Territories, Canada.
Its associates. In kimberlite pipes, forsterite, phlogopite, pyrope, diopside and ilmenite; in placers, ilmenite, garnet, rutile, brookite, anatase, hematite, magnetite, tourmaline, gold, zircon and topaz. Gold’s own status as a mineral is on is gold a mineral.
The classification questions are indexed at the collecting guides. Nothing on this site is offered for sale; the wanted list is the only commercial route.