Though most of these haven't been verified by
actual chemical analysis, I've tried to keep this list as reliable as possible.
Again, I want to keep this list restricted [mostly] to minerals that you
might find at the Mine Run Dump or in the old Pits. Also, this page does
not refer to specimens from the "world minerals" pile or ones that I suspect
were dragged over from that region. That area of the dump contains plenty
of really neat specimens from who-knows-where, but I'm concentrating on definite
Sterling Hill material here. If it's of doubtful origin, I'm not going to
publish it without first asking one of the museum people.
ACTINOLITE: Small, needlelike green crystals are also found at Sterling Hill (just as they are at Franklin), associated with franklinite / willemite ores, as well as some of the rock that was outside the actual ore body. Noble / Passaic Pit rocks are worth checking for nice actinolite sprays, ranging from 3 mm to 1 cm long.
ANGLESITE: Lead sulfate. I'm told it's rare at Franklin /
Sterling Hill. It has been found in minute quantities as thin coatings on
galena, but I guess it's not found here in crystals. One would imagine lead
sulfate to be much more common than it apparently is; there is galena at
Sterling Hill, along with sphalerite and pyrite. The weathering of these
together should (in theory) produce lead sulfate.
ARAGONITE - not usually found as crystals, but the massive
form is definitely there, so there's potential.
AURICHALCITE: Can be found in cavities in weathered augite
("jeffersonite"), along with cerussite, hemimorphite, galena, goethite, and
actinolite. Specimens have been reported as bright blue.
CALCITE - Micro crystals in cavities from the walls of the
Passaic Pit; these fluoresce orange to yellow in short-wave UV. Some
of the crystals have the classic "dog tooth" / scalenohedral habit, although
they're quite small.
CERUSSITE: Lead carbonate. Found as microcrystals lining cavities in weathered galena-bearing rock which was dragged over from the Noble and Passaic pits. Some of the crystals are exceptionally well-formed, though tiny. Cerussite also occurs as crusts or coatings on the weathered galena. Some of it fluoresces, but there are two conflicting versions of its color: one says that it's primarily bluish-cream under SW, while the other says it's mostly yellowish under LW. Most sources claim the latter to be true. Maybe there are two different activators or something. I have found spots of what appears to be cerussite in the Noble Pit rocks which do fluoresce a distinct yellow under LW, faintly under SW.
CHALCOPHANITE: I've seen a couple of micro specimens come off the Mine Run Dump which appeared to be chalcophanite. Perhaps they were hetaerolite, though. I'm currently on a hetaerolite kick. I must find hetaerolite (see below)!
CHLOROPHOENICITE: I found one 8-cm piece of franklinite / zincite / willemite ore that had 1- to 2-mm pockets and spots containing "puffy"-looking white material, visible only under about 20x magnification. Some of this material has a metallic coating that gives it the appearance of rutile. I took the specimen over to the Franklin museum and John Cianciulli told me it's most likely chlorophoenicite with a thin coating of some manganese compound (hetaerolite, perhaps??). UPDATE: 3/26/2000... I found a little bit more of this material in some ore pieces at Sterling Hill. The crystals are exceedingly small, barely visible with a good hand lens.
CHRYSOCOLLA: A silicate of copper. Has been reported in tiny amounts in weathered augite cavities.
DIOPSIDE: Dark green microcrystals can occur in the rock from the Noble Pit, as well as in the rock from the quarries of the area. Some collectors have told me that the mineral found with the wollastonite in the Noble Pit is gahnite, but others are sure it's diopside. Right now I tend to side with the diopside crowd; I've yet to see an octahedral crystal of that mysterious dark green stuff. Furthermore, visual comparison with known specimens of diopside, especially the dark, iron-green "gem rough" material floating around on eBay, suggests it is in fact diopside.
FRANKLINITE: Sterling Hill franklinite crystals are usually much larger than those found on the Buckwheat dump. They can be a centimeter or more across, and sometimes very sharply formed. Some of the best ones occur in a brittle calcite matrix, while others occur in a matrix of bright red zincite.
FRIEDELITE: Some microcrystals of this mineral have been found on the Mine Run Dump, associated with tiny crystals of hemimorphite. I don't have any other information on this mineral right now. I will try to find out more details about this find.
GAHNITE: A dark green zinc-spinel. Forms octahedral crystals; also found in massive form. Most of this material apparently comes from the Passaic Pit. As always, the massive form is more common than the well-crystallized variety. Sometimes you can find sharp octahedral microcrystals of gahnite on the Mine Run Dump. Back in the old Pits, crystals 2 cm across (!) turn up once in a while on the special field trips they have twice yearly.
GALENA: found as small, shiny-faced cleavage masses (though sometimes weathered & tarnished), with sphalerite and cerussite. Galena itself is not that exciting here if you're looking for crystals, but I think it's interesting that you can find this mineral in New Jersey. Larger specimens are somewhat rare from the Franklin / Sterling Hill area.
HEMIMORPHITE: A silicate of zinc. Transparent to translucent white, the crystals can be up to 5 mm across, and are generally tabular. They are usually in groups, but I've found isolated ones. Many times they have a thin coating of dried mud or soil which won't come off with ultrasonic cleaning. Hemimorphite can also be found as botryoidal masses or crystalline spherules. I've found it in the galena / sphalerite-bearing rock from the Passaic pit, sometimes with small spots of hydrozincite near it. The biggest recent find of hemimorphite at Sterling Hill was in the Passaic Pit around a huge boulder they unearthed a couple of years back. It's mostly gone now, but there are still potato-sized specimens lurking around back there, rife with hemimorphite microcrystals.
HETAEROLITE: Definitely a Sterling Hill mineral, and I suspect
it can be found as micro specimens on the Mine Run Dump. Since hetaerolite
so often occurs as inclusions in zincite, and since zincite is easily found
on the Mine Run Dump, I'd guess you could find micro-specimens of actual
hetaerolite by itself too. This mineral is an oxide of manganese and zinc,
is in the tetragonal crystal system, and forms tiny pseudo-octahedral crystals
or pyramids. It is black and can be lustrous. I want to find some!
MAGNETITE crystals have been found back in the Noble Pit.
Some have been quite large, on the order of one to two inches or even
MALACHITE: At least one specimen has been reported recently from the Mine Run Dump at Sterling Hill. It was found with franklinite, willemite, and calcite, and occurred in cavities as spherical aggregates about 1 or 2 mm across. This was during the F.O.M.S. field trip of Sept. 20, 1997. On October 25, 1998 the guy I was collecting with found a couple micro specimens of what appeared to be malachite. One of them was particularly nice.
MIMETITE: (or similar mineral in the mimetite-pyromorphite series) I found two specimens of this mineral in weathered galena-bearing rock from the Noble Pit which was cast on the Mine Run Dump. They are bright yellow-orange hexagonal prisms, visible with a hand lens, about 1 to 2 mm in length. The matrix is unmistakeably Sterling Hill rock, not foreign or "world minerals" stuff.
TOURMALINE (var. SCHORL): appears as black, radiating needles or narrow prisms in a matrix of scapolite or feldspar. The crystals I've found are up to 0.5 cm in length, but are not all that distinct because they are not in open pockets. Look through enough rock and you may find a well-formed micromount specimen or two from Sterling Hill.
WILLEMITE: Pinkish or tan, opaque willemite crystals, some of which are quite large, occur at Sterling Hill. Some willemite crystals can be found with good terminations, especially in the crumbly, coarse-grained franklinite / tan willemite ore that is scattered throughout the dump. Usually they fall out of the matrix. They are brightly fluorescent and phosphorescent, SW, with some LW activity. I would imagine there'd be actual, sharp micro crystals of transparent or translucent willemite at Sterling Hill, though I haven't found any yet. UPDATE: 3/26/2000- found some of those micro crystals... two kinds... (1) a very small rock containing pink, bladed crystals that looked like rhodonite at first glance; (2) secondary, tufted / needle-like crystals which fluoresce with extreme brightness under shortwave. I found both in the same day while looking for chlorophoenicite.
WOLLASTONITE: Small, orange-fluorescing grains of this mineral occur scattered through calcite that has been found in the Noble Pit. It occurs with what small grains / microcrystals of what appears to be a dark green diopside. There was a large boulder of wollastonite in calcite back there in the old Pit. If you take apart enough pieces of this material, you might find a well-formed micro crystal of wollastonite. Don't take apart good, large fluorescent specimens, though. : )