Is chrysoprase chalcedony?
Yes. Chrysoprase is green chalcedony, quartz coloured by nickel: 8,450 ppm on average in a 2024 study, 3 ppm in agate. Hardness 7; dyed or chrome greens differ.
Yes. Chrysoprase is chalcedony: translucent, apple-green microcrystalline quartz coloured by nickel, hardness 7, specific gravity 2.60 ± 0.05 (Hobbs, 1982). A 2024 Mineralogical Magazine study measured 8,450 ppm nickel on average in chrysoprase against 3 ppm in agate. Dyed green or chromium-green chalcedony is still chalcedony, but it is not chrysoprase.
In short
- The definition. The International Gem Society chalcedony article defines chrysoprase as translucent green chalcedony colored by nickel, and adds that it may resemble fine jade. The USGS gemstones list puts chrysoprase among the cryptocrystalline varieties of silica under quartz. A script over the September 2026 IMA-CNMNC Master List finds rows for quartz and none for chrysoprase or chalcedony: the mineral is quartz, and chrysoprase is a variety name.
- The nickel ledger. Monico and co-authors, Mineralogical Magazine 88 (2024) measured nickel by laser-ablation ICP-MS: 8,450 ppm on average in chrysoprase (951 to 17,544, 10 analyses), 280 ppm in the bluish-green areas of aquaprase and 3 ppm in agate. Worked, 8,450 ppm is 0.845 wt% nickel or 1.08 wt% NiO, about 2,800 times the agate average and 30 times aquaprase’s. The lowest chrysoprase reading, 951 ppm, is above the highest aquaprase one, 536.
- The Ni-over-Cr check. On the same averages chrysoprase holds about 367 times as much nickel as chromium (8,450 against 23 ppm); aquaprase holds 0.22 (280 against 1,253), and the paper names chromium as aquaprase’s main colouring element. Both are green chalcedony; on the IGS definition, coloured by nickel, only the first is chrysoprase. This check needs an analysis, not an eye.
- Documented failure: the balance. At Hobbs (1982)’s 2.60 ± 0.05, a 20.00 g piece reads 12.16 to 12.45 g in water. Dyed green chalcedony is the same material and reads the same. variscite at the sheet’s 2.57 to 2.61 reads 12.22 to 12.34 g, inside that window, though its hardness is 4.5 against 7. jadeite (at least 13.83 g) and prehnite (at least 12.86 g) are heavier.
- The colour cause is disputed. Monico and co-authors call the origin of chrysoprase colour a controversial topic: willemseite, ‘kerolite’ or ‘pimelite’ (names they say are now discredited), or bunsenite, NiO. Their own Raman work found willemseite. The IMA list has rows for willemseite and bunsenite and none for kerolite or pimelite.
| Label | What it is (source) | Green from (source) | Hardness | SG or density | 20.00 g piece in water | IMA row? | Is it chrysoprase? |
|---|---|---|---|---|---|---|---|
| Chrysoprase | Translucent green chalcedony (IGS) | Nickel (IGS); Ni average 8,450 ppm (Monico) | 7 (Hobbs) | 2.60 ± 0.05 (Hobbs) | 12.16 to 12.45 g | No; quartz yes | Yes |
| Dyed green chalcedony | Chalcedony with dye (IGS; Hobbs) | Dye: pink in the Chelsea filter (IGS); narrow red bands (Hobbs) | 7 | As chalcedony | As chrysoprase | No; quartz yes | No: same weight, test by instrument |
| Aquaprase | Bluish-green chalcedony, a trade name (Monico) | Chromium, up to 2,703 ppm (Monico) | Not given | Not given | - | No | No: chromium green |
| Chrome chalcedony | A chalcedony variety (IGS list); rare chrome-coloured chalcedony (Hobbs) | Chromium (Hobbs) | 7 | As chalcedony | - | No | No |
| Prase | Green or yellowish green chalcedony (IGS) | Not stated by IGS | 7 | As chalcedony | - | No | No: a different variety name |
| “Queensland jade” | Hobbs’s misleading term for chrysoprase | As chrysoprase | 7 | As chrysoprase | As chrysoprase | No | Yes, misnamed |
| Variscite | Al(PO4)(H2O)2 (IMA) | - | 4.5 (sheet) | 2.57 to 2.61 (sheet); 2.2 to 2.57 (IGS) | 12.22 to 12.34 g | Yes | No: soft |
| Aventurine quartz | Quartzite with fuchsite (IGS) | Chromium mica platelets (Hobbs) | 7 (Hobbs) | 2.66 ± 0.01 (Hobbs) | 12.45 to 12.51 g | No; quartz yes | No: it glitters |
| Jadeite | NaAlSi2O6 (IMA) | - | 6 to 7 (sheet) | 3.24 to 3.43 (sheet) | 13.83 to 14.17 g | Yes | No: heavier |
| Prehnite | Ca2Al(Si3Al)O10(OH)2 (IMA) | - | 6 to 6.5 (sheet) | 2.80 to 2.95 (sheet) | 12.86 to 13.22 g | Yes | No: heavier |
Is chrysoprase chalcedony? The definition in one sentence
Chrysoprase is chalcedony, the microcrystalline form of quartz, in its translucent green, nickel-coloured variety. The International Gem Society chalcedony article lists chrysoprase among the chalcedony varieties as translucent green chalcedony colored by nickel, and gives the chalcedony panel hardness 7, refractive index 1.540 to 1.553 and specific gravity 2.55 to 2.91. Hobbs, The Jade Enigma (Gems and Gemology, Spring 1982) gives chrysoprase itself RI 1.535 to 1.539, spot 1.53, specific gravity 2.60 ± 0.05 and hardness 7, with even colour. Monico and co-authors, Mineralogical Magazine 88 (2024) call it the chalcedony variety much appreciated for its apple green colour, with its most famous localities in Australia.
On the IMA list it is quartz. A case-insensitive scan of the September 2026 list finds no line containing chrysoprase, chalcedony or prase, and a row for quartz, SiO2, status A, 1967 s.p. Whether chalcedony counts as quartz, and the rule for choosing between the two words, are on is chalcedony quartz; chalcedony’s quartz-and-moganite composition is on chalcedony. Neither is repeated here.
Where it comes from. The IGS gives chrysoprase sources as Western Australia (Yandramindra, Wingelina, Kalgoorlie), Brazil, California and Russia, and its quartz article records chrysoprase nodules of 700 and 1,470 kilos found near Kalgoorlie. The two chrysoprase samples in the 2024 study were from the Rockhampton region, Australia.
What makes chrysoprase green? The nickel ledger
Nickel: chrysoprase averaged 8,450 ppm nickel against 3 ppm in agate, in the same laboratory. the 2024 Mineralogical Magazine study reports laser-ablation ICP-MS trace elements in its Table 4: chrysoprase, 10 analyses, nickel average 8,450 ppm, range 951 to 17,544; aquaprase, bluish-green areas, 14 analyses, average 280, range 80 to 536; agate, 15 analyses, average 3, range below detection to 25. The text rounds the chrysoprase maximum to 17,500 ppm. Electron-microprobe analyses found variable NiO up to 5 wt% in the brighter zones, and the chrysoprase formula in its Table 3 carries 0.045 nickel atoms per two oxygens.
The ledger, worked. 1 wt% is 10,000 ppm, so 8,450 ppm is 0.845 wt% nickel; multiplying by 74.692/58.693, the mass ratio of NiO to Ni, gives 1.08 wt% NiO. The maximum, 17,544 ppm, is 1.75 wt% nickel or 2.23 wt% NiO; the minimum, 951 ppm, 0.12 wt% NiO. The averages put chrysoprase about 2,800 times above agate and 30 times above aquaprase, and every chrysoprase reading, from 951 ppm up, is above every aquaprase and agate reading. Substitute any analysis in the same arithmetic.
The Ni-over-Cr check. Chromium averages 23 ppm in chrysoprase and 1,253 ppm in aquaprase’s bluish-green areas, maximum 2,703. Nickel over chromium is therefore about 367 in chrysoprase and 0.22 in aquaprase, whose bluish-green the paper attributes to chromium. Two green chalcedonies, two different colouring elements: on these figures, a chalcedony is chrysoprase when nickel, not chromium, carries the green. It is a laboratory check, and this page does not claim it can be made by eye.
Is the colour cause settled? Four candidates on record
No: the 2024 paper calls the origin of chrysoprase colour a controversial topic and lists the candidates. Monico and co-authors, Mineralogical Magazine 88 (2024) write that some authors attribute the colour to finely dispersed nickel-bearing layered silicates such as willemseite (Eggleton et al., 2011) or ‘kerolite’ and ‘pimelite’, the latter two now discredited as formal mineral names, and that others attribute it to evenly distributed bunsenite, NiO, crystallites (Jiang and Guo, 2021). Their own micro-Raman work confirmed willemseite, and they conclude that chrysoprase’s apple-green is due to nickel phyllosilicate inclusions.
What the IMA list says about each candidate. Willemseite has a row, Ni3Si4O10(OH)2, status A, 1971 s.p., South Africa. Bunsenite has a row, NiO, status G, 1868, Germany. A case-insensitive scan finds 0 lines containing kerolite or pimelite, which agrees with the paper. So of the four names in the dispute, two are current species and two are not; all four candidates carry nickel.
What this page does not add. It gives no colour mechanism beyond those attributed statements and no treatment beyond dyeing. On fading, the International Gem Society question-and-answer on chrysoprase fading answers that chrysoprase whose colour is natural and not dyed won’t fade; the answer rests on a cutter’s pieces worn since the 1960s, not on a test, and is reported here as that.
What is not chrysoprase: dyed, chrome and look-alike greens
Dyed green chalcedony is the documented failure: same material, same weight, different colourant. The IGS chalcedony article says dyeing is an ancient and common practice, that chalcedonies are relatively porous, and that dyed blue and green gems show pink in the Chelsea filter. Hobbs (1982) writes that dyed green chalcedony, and rare chrome-coloured chalcedony, may show narrow bands in the red of the spectrum without the shading between them that jadeite shows. Both are instrument tests. At 2.60 ± 0.05 a 20.00 g piece of either reads 12.16 to 12.45 g in water, so a balance cannot tell them apart. General dye checks are on how to tell if a crystal is dyed; the method for weighing is on how to measure specific gravity at home.
Jade and its names. Hobbs lists “Queensland jade” as a misleading term for chrysoprase, and the IGS says chrysoprase may resemble fine jade. jadeite on its sheet is 3.24 to 3.43, so a 20.00 g piece reads 13.83 to 14.17 g, about 1.4 g or more above chrysoprase’s highest reading. The jade names and tests are on is jade a mineral and how to tell if jade is real and are not repeated here.
Variscite, prase and aventurine. variscite reads 12.22 to 12.34 g on its sheet, inside chrysoprase’s window, but its hardness is 4.5 against 7; the IGS gives variscite a lower SG, 2.2 to 2.57, than the sheet does. Prase, on the IGS articles, is green or yellowish green chalcedony, a separate variety name. Aventurine quartz glitters with mica, which chrysoprase does not; see is aventurine a quartz. The other identification pages are at the collecting guides. Nothing on this site is offered for sale; the wanted list is the only commercial route.