Is galena magnetic
No. The galena sheet records no magnetism, and USGS found 9 of 9 galena samples unpulled at 1.70 amp. In a galena specimen, whatever is pulled is not galena.
Is galena magnetic? No, on both records. The Handbook sheet for galena, PbS, hardness 2.5 to 2.75, density 7.58, records no magnetic property, and USGS Open-File Report 99-529 left all 9 galena samples unpulled at 1.70 amp, its separator maximum: diamagnetic by that report's definition. So a pull on a galena specimen comes from another mineral.
In short
- The reference sheet is silent. The Handbook of Mineralogy sheet for galena gives PbS, cubic, perfect cleavage on {001}, hardness 2.5 to 2.75 and measured density 7.58, and the string magnet does not occur anywhere on it. Silence is absence from the source, not a measurement, which is why the next point matters.
- USGS measured it, nine times. Rosenblum and Brownfield passed galena grains, 125 to 150 µm, through a laboratory magnetic separator. All 9 samples stayed behind at 1.70 amp, the highest current their machines reached. The report calls such minerals diamagnetic: nonmagnetic at 1.70 amp.
- The stay-behind rule: on a separator, galena is what is left when the magnetic minerals have gone. Of the 9 associates the galena sheet names that are tabled here, 3 (marcasite, chalcopyrite, siderite) have a USGS best range inside the paramagnetic range, 6 stay behind with galena, and none is ferromagnetic.
- Dark and metallic does not mean magnetic. USGS writes that dark-coloured and opaque minerals are generally extracted below 1.00 amp, and names many sulfides among the exceptions. Galena, lead-gray and opaque, is one: no iron or copper is in PbS, and USGS names those two elements as responsible for paramagnetism in some minerals.
- A pull is information about something else. Neither source tests a hand magnet, so this page does not predict one. USGS reserves strongly attracted to a magnet for ferromagnetic minerals such as magnetite and pyrrhotite, and galena is not on that list.
| Mineral | Magnetism on the Handbook sheet | USGS total range (amp) | USGS best range (amp) | Samples | Class, by USGS definitions |
|---|---|---|---|---|---|
| Galena | None recorded | Above 1.70 | Above 1.70 | 9 | Diamagnetic: stays behind |
| Sphalerite | None recorded | 1.30 to above 1.70 | Above 1.70 | 8 | Best range diamagnetic |
| Sphalerite-(Fe), as USGS lists iron-bearing sphalerite | Sheet formula (Zn,Fe)S; none recorded | 0.20 to 1.20 | 0.60 to 1.00, depends on chemistry | 6 | Paramagnetic |
| Marcasite | None recorded | 0.30 to above 1.70 | 0.60 to 1.00, depends on chemistry | 2 | Paramagnetic |
| Chalcopyrite | None recorded | 0.30 to 1.70 | 0.70 to 1.30, depends on chemistry | 8 | Paramagnetic |
| Siderite | None recorded | 0.10 to 0.50 | 0.20 to 0.30 | 17 | Paramagnetic |
| Tetrahedrite | None recorded | Above 1.70 | Above 1.70 | 5 | Diamagnetic |
| Calcite | None recorded | Above 1.70 | Above 1.70 | 8 | Diamagnetic |
| Dolomite | None recorded | Above 1.70 | Above 1.70 | 4 | Diamagnetic |
| Baryte (USGS: barite) | None recorded | Above 1.70 | Above 1.70 | 6 | Diamagnetic |
| Quartz | None recorded | Above 1.70 | Above 1.70 | 10 | Diamagnetic (often locked with other species) |
| Magnetite, for scale | Strongly magnetic | Below 0.01 to 0.05 | 0.01 | 6 | Ferromagnetic |
| Pyrrhotite, for scale | Magnetic, varying in intensity inversely with iron content | Below 0.01 to 0.70 | 0.01 to 0.05 | 7 | Ferromagnetic |
Is galena magnetic? What the Handbook sheet records
The Handbook of Mineralogy sheet for galena records no magnetic property. It gives PbS, cubic, most commonly as cubes, with perfect cleavage on {001}, subconchoidal fracture, brittle tenacity, hardness 2.5 to 2.75 and measured density 7.58. Colour and streak are both lead-gray, lustre metallic. A sheet that records pyrrhotite as Magnetic, varying in intensity inversely with iron content and magnetite as Strongly magnetic has the vocabulary; on galena it uses none of it.
Method. The galena sheet and the sheets of the 9 associates in the table, all saved as text with pdftotext -layout, were searched by script, case-insensitively, for the string magnet. It occurs on none of the ten galena-and-associate sheets in its Physical Properties field. Silence on a reference sheet is absence from the source, not a measured zero, so the question goes to a measurement. The species itself is on galena.
Galena is 86.60% lead by mass, from standard atomic weights, Pb 207.2 and S 32.06, and the sheet's ideal column prints the same figure. Its two analyses add only traces: copper 0.07% in the Katanga sample, assumed to sit in covellite, and copper as a trace in the Barrow mine sample from Newlands, Cumbria. The lead question belongs to is galena toxic, not here.
What the USGS separator measured: 9 of 9 samples stayed behind
USGS measured galena's response, and it is below the reach of the instrument. USGS Open-File Report 99-529, Magnetic Susceptibilities of Minerals (Rosenblum and Brownfield) fed dry grains, 125 to 150 µm, through a Frantz isodynamic separator at a 15 degree side tilt and recorded the current at which each mineral was pulled. For galena, 9 samples, both the total range and the best range read above 1.70 amp, the highest current reached on most of the machines used.
The report's definitions, as written. Ferromagnetic refers to minerals strongly attracted to a magnet, like a piece of iron, and the report names magnetite, maghemite, pyrrhotite and pentlandite. Paramagnetic minerals are less magnetic than that and separable at up to 1.70 amp. Diamagnetic refers to minerals that are nonmagnetic at 1.70 amp and would be repelled by electromagnets with stronger currents. On those definitions galena is diamagnetic. The report does not measure susceptibility in cgs units, so this is a classification, not a number for galena's susceptibility.
Why a dark mineral can stay behind. USGS writes that dark-coloured and opaque minerals are generally extracted at less than 1.00 amp, and lists the exceptions as including red tourmaline, red rutile, some corundum, microlite, cassiterite and many sulfides. It names iron and copper as two elements responsible for paramagnetic susceptibility in some minerals. PbS contains neither; we note that as consistent with the measurement, not as a proof of its cause. Rhodochrosite, by contrast, is pulled from 0.10 amp, as set out on is rhodochrosite magnetic.
The stay-behind rule: what else in a galena specimen is pulled
The stay-behind rule: in a galena specimen, anything a magnetic separator pulls is not galena. The galena sheet's Association field names sphalerite, marcasite, pyrite, chalcopyrite, tetrahedrite, silver minerals, siderite, calcite, dolomite, barite and quartz. Nine of those have their own row in the USGS table and are set out above. Counted over those 9: marcasite, chalcopyrite and siderite have a best range inside the paramagnetic range; sphalerite, tetrahedrite, calcite, dolomite, baryte and quartz stay behind with galena; none is in the report's ferromagnetic class.
Iron-bearing sphalerite is the case to watch. USGS lists plain sphalerite with a best range above 1.70 amp, but a separate row, Sphalerite-(Fe), at 0.20 to 1.20 amp. The sphalerite sheet writes the formula (Zn,Fe)S. A dark sphalerite in a galena vein may therefore be pulled where galena is not. Neither sheet records this; the separation is USGS's. Pyrite, also a listed associate, is left out of the table deliberately: the two sources used here do not agree about it, and this page does not choose between them.
Galena's own alteration minerals stay behind too. The same table gives cerussite (3 samples), pyromorphite (3), mimetite (2) and vanadinite (2) all above 1.70 amp. So the lead minerals collected alongside galena, cerussite and pyromorphite among them, give the separator nothing to pull either. Sheets that do record magnetism are discussed on which minerals are magnetic.
My galena pulls a magnet: what that means
A pull on a galena specimen is a second mineral, steel left by a tool, or a misidentified specimen. On the USGS definitions only ferromagnetic minerals are strongly attracted to a magnet, and galena is not among them. The report adds that micro-inclusions of magnetite or other ferromagnetic minerals make a lower limit of extraction hard to determine, and that a sample pulled from 0.10 amp yet best above 1.70 amp suggests contamination by a ferromagnetic mineral. Neither the report nor the Handbook tests a hand magnet, so we predict nothing about one.
Localise the pull, then test the grain. That sequence, and how magnetite and pyrrhotite are told apart by colour, streak and hardness, is set out on is tetrahedrite magnetic and applies unchanged; it is not repeated here. A lead-gray streak on a streak plate and stepped cleavage cubes confirm the galena itself.
Is galena a metal? No: a sulphide mineral, the ore of lead. The identification guides are indexed at the collecting guides. Nothing on this site is offered for sale; the wanted list is the only commercial route.