Shattuckite vs chrysocolla
Two copper silicate species. Shattuckite: density 4.11, 2.03–2.75% water. Chrysocolla: 1.93–2.4, 9.60–19.46%. In water, 20 g reads 15.13 g or 9.64–11.67 g.
No. Shattuckite and chrysocolla are both blue copper silicates, but they are different minerals. Shattuckite, Cu5(SiO3)4(OH)2, has density 4.11 and 2.03 to 2.75% water in its sheet analyses; chrysocolla has 1.93 to 2.4 and 9.60 to 19.46% water. A 20.00 g piece reads 15.13 g in water as shattuckite and 9.64 to 11.67 g as chrysocolla.
In short
- Two species, two very different IMA rows. The September 2026 IMA-CNMNC Master List lists shattuckite as Cu5(SiO3)4(OH)2, status Rd, 1967 s.p., USA, with a type locality at the Shattuck mine, Bisbee, per its Handbook of Mineralogy sheet. Chrysocolla is (Cu2-xAlx)H2-xSi2O5(OH)4·nH2O, status A, 1980 s.p., country unknown, first reference printed as “original paper?”. Its sheet gives the crystal system as orthorhombic (?) and the point group as n.d.
- The water ledger. Every analysis on the two sheets, set side by side: shattuckite 2.66% H2O at Ajo, 2.03% at Mili and 2.75% ideal; chrysocolla 19.46% at Mednorudyansk (10.00 H2O+ and 9.46 H2O−) and 9.60% at Kamoya (8.29 and 1.31). The least watery chrysocolla carries 3.5 times the water of the most watery shattuckite. Copper runs the other way: 47.13 to 48.43% against 33.55 and 37.49%.
- The clean separators. Density 4.11 against 1.93 to 2.4, so a 20.00 g piece reads 15.13 g in water against 9.64 to 11.67 g, 3.47 g apart. Refractive index 1.753 to 1.815 against 1.575 to 1.635, 0.118 apart. Cleavage perfect on {010} and {100} against none printed and a conchoidal fracture. Lustre silky against vitreous, porcelaneous or earthy.
- Documented failure: hardness, colour and mixtures. Shattuckite’s about 3.5 lies inside chrysocolla’s about 2 to 4. Both sheets print blue. The shattuckite sheet names chrysocolla first among its associates, so a crust can be both, and a mixed piece reads between the two figures. Weight does not part shattuckite from malachite, either: 15.13 g against 15.06 g.
- The decision. Weigh a solid piece in water. Near 15.1 g for 20.00 g is the shattuckite reading, 9.6 to 11.7 g the chrysocolla reading, and anything between says mixed or something else. Then look: deep blue silky needles and spherules for shattuckite, an opaline or earthy crust for chrysocolla. The species pages are shattuckite and chrysocolla.
| Property | Shattuckite (sheet) | Chrysocolla (sheet) | Separates? |
|---|---|---|---|
| Formula (IMA) | Cu5(SiO3)4(OH)2 | (Cu2-xAlx)H2-xSi2O5(OH)4·nH2O | Yes |
| IMA status | Rd, 1967 s.p.; USA | A, 1980 s.p.; country unknown | — |
| Crystal system | Orthorhombic, Pcab | Orthorhombic (?); space group n.d. | No |
| Habit | Rarely prismatic crystals to 2 mm; spherulitic masses of acicular crystals | Acicular crystals to 5 mm in radiating clusters; fibrous, botryoidal, earthy; commonly cryptocrystalline, opaline or enamel-like | Partly |
| Hardness | ~3.5 | ~2–4 | No: 3.5 lies inside |
| Density | 4.11 | 1.93–2.4 | Yes: 1.71 to 2.13 times |
| 20.00 g piece in water | 15.13 g | 9.64–11.67 g | Yes: 3.47 g apart |
| Colour | Deep to medium blue | Blue, blue-green or green; brown to black when impure | No: both blue |
| Streak | None printed | White when pure | Not on the sheets |
| Lustre | Silky | Vitreous, porcelaneous, earthy | Usually |
| Cleavage, fracture | {010} and {100}, perfect | None printed; conchoidal fracture | Yes, on a crystal |
| Refractive indices | α 1.753, β 1.782, γ 1.815; biaxial (+) | α 1.575–1.585, β 1.597, γ 1.598–1.635; biaxial (−) | Yes: 0.118 apart |
| Birefringence, worked | 0.062 | 0.013–0.060 | No |
| Water in the analyses | 2.66%, 2.03%, 2.75% (ideal) | 19.46%, 9.60% | Yes: 3.5 to 9.6 times |
| Copper in the analyses | 48.26%, 47.13%, 48.43% (ideal) | 33.55%, 37.49% | Yes |
| Cu:Si in the analyses | 1.244, 1.198, 1.250 (ideal) | 0.886, 0.898 | Yes |
Is shattuckite the same as chrysocolla?
No. Shattuckite is a fixed-formula copper silicate with a type locality; chrysocolla is a variably hydrated one with neither. The Handbook shattuckite sheet gives Cu5(SiO3)4(OH)2, orthorhombic, space group Pcab, named for its type locality, the Shattuck mine at Bisbee, Arizona. The Handbook chrysocolla sheet gives (Cu,Al)2H2Si2O5(OH)4·nH2O, orthorhombic with a question mark, point group not determined, and no type locality.
The IMA list, exactly as printed. Shattuckite: Cu5(SiO3)4(OH)2, Rd, 1967 s.p., USA. Chrysocolla: (Cu2-xAlx)H2-xSi2O5(OH)4·nH2O, A, 1980 s.p., country unknown, first reference “original paper?”, second reference Comptes Rendus de l’Académie des Sciences de Paris 271 (1970), 1837. Chrysocolla is an approved species on that list; it is simply recorded with two open variables, x and n. The chrysocolla species page sets out what the references do not know about it, and is not repeated here.
Why the question gets asked. Both are blue, both are copper silicates of oxidised copper deposits, and the shattuckite sheet names chrysocolla first among its associates. Evans and Mrose (1977) write that the close association of shattuckite and planchéite with each other and with chrysocolla and dioptase, and the difficulty of obtaining really pure bulk samples, long left their chemistry uncertain.
How much water is in shattuckite and chrysocolla? The water ledger
Every chrysocolla analysis on its sheet carries roughly 3.5 to 9.6 times the water of the shattuckite analyses on its sheet. Method: the H2O figures were read from each sheet’s Chemistry block, adding H2O+ and H2O− for chrysocolla, and copper and Cu:Si worked from the CuO and SiO2 figures on standard atomic weights. Shattuckite: Ajo 2.66% H2O, 48.26% copper, Cu:Si 1.244; Mili, Evvia, by microprobe with water by difference, 2.03%, 47.13%, 1.198; the ideal formula 2.75%, 48.43%, 1.250. Chrysocolla: Mednorudyansk 19.46%, 33.55%, 0.886; Kamoya 9.60%, 37.49%, 0.898.
What the ledger says. The ratio of water runs from 3.5 (9.60 against 2.75) to 9.6 (19.46 against 2.03). The ideal shattuckite formula is exact: CuO 60.62%, SiO2 36.63%, H2O 2.75%, the sheet’s third column. Chrysocolla has no ideal column, because its formula ends in nH2O; its two analyses differ from each other by a factor of two in water. That spread, and its density of 1.93 to 2.4, are what the sheet prints; this page gives no mechanism linking them.
Who the ledger is for. A collector with an analysis, or a label quoting one, can place it at once: about 2 to 3% water and Cu:Si near 1.2 to 1.25 reads as shattuckite, 9.6% water or more and Cu:Si under 1 as chrysocolla. Planchéite’s Mindouli analysis, at Cu:Si 1.20 but 4.50% water, shows why both columns are needed; the shattuckite page sets it out. Without an analysis, use the balance in the next section.
How do you tell shattuckite from chrysocolla? Weight first
A 20.00 g solid piece reads 15.13 g in water as shattuckite and 9.64 to 11.67 g as chrysocolla. The densities are 4.11 and 1.93 to 2.4, so shattuckite is 1.71 to 2.13 times as dense, and the two readings are 3.47 g apart at the nearest. The method, and how large a piece needs to be for the reading to mean anything, is on how to measure specific gravity at home. The chrysocolla figure matches is chrysocolla the same as turquoise and is chrysocolla the same as malachite.
The other separators. Optics: shattuckite’s lowest index, α 1.753, is 0.118 above chrysocolla’s highest, γ 1.635, and the signs differ, biaxial (+) against biaxial (−). Cleavage: shattuckite perfect on {010} and {100}; chrysocolla none printed, fracture conchoidal. Lustre: silky against vitreous, porcelaneous or earthy. Habit: shattuckite as spherulitic masses of acicular crystals; chrysocolla commonly cryptocrystalline, opaline or enamel-like.
Streak, not on these sheets. The chrysocolla sheet prints white when pure; the shattuckite sheet prints no streak at all, so this page gives no streak test for shattuckite. The plate itself is on how to use a streak plate.
Where the easy tests fail, and what goes on the label
Documented failure: hardness and colour. Shattuckite is about 3.5 and chrysocolla about 2 to 4, so a scratch that marks one may mark the other; how to test mineral hardness properly covers the method. Shattuckite is deep to medium blue; chrysocolla blue, blue-green or green. Colour narrows the field to blue copper minerals and stops there.
Documented failure: mixtures and near neighbours. Because the shattuckite sheet lists chrysocolla as an associate, a single crust can hold both, and a whole-piece weighing then lands between 11.67 and 15.13 g, matching neither. The shattuckite sheet’s Ajo analysis was itself recalculated after deducting 0.58% quartz. At the heavy end, malachite reads 15.06 g, 0.07 g from shattuckite, and planchéite 14.52 to 14.74 g; the shattuckite page shows how hardness and colour part those.
On the label. Write shattuckite when a piece reads near 15.1 g and is deep blue and silky; chrysocolla when it reads 9.6 to 11.7 g; and both, or copper silicates, when the crust is plainly mixed. Shattuckite and chrysocolla are copper compounds; for handling questions see toxic minerals in a collection or a clinician: this page is not advice. More identification questions are at the collecting guides. Nothing on this site is offered for sale; the wanted list is the only commercial route.