MAGNETITE: I've found tiny, sharp octahedrons at Lime Crest. Magnetite is in the spinel group, but it's perfectly opaque-- and magnetic.
MARGARITE: Bright lime-green or bluish-green micaceous / foliated masses. More commonly, dull gray. Found at the Franklin ("Farber") quarry in moderate amounts, usually with a light brown variety of mica (phlogopite?) and sometimes with rutile. Margarite adds color to your daylight mineral collection, but good specimens showing vivid color are very uncommon.
silvery, thin, hexagonal plates and
confused with graphite, occur at the quarries. Molybdenite can form
"barrel"-shaped crystals which have perfect basal cleavage (much like
mica crystals). I have not found any of these yet from the Sussex Co.
quarries. This morphology would be easiest to distinguish from
graphite, but when they're just individual flakes, it's a bit
tougher. Molybdenite is of course a sulfide, so there's always
the chemical tests.
NORBERGITE and CHONDRODITE: Yellow to honey-brown, found as multiple grains in the altered limestone in both the Franklin and the Lime Crest quarries. Some norbergite specimens are exceptionally fluorescent (yellow under SW), and some occur with brightly-fluorescent (bluish-white SW) grains of DIOPSIDE. Occasionally you'll find a well-formed, small crystal of chondrodite or norbergite, but the majority are anhedral or just misshapen and with poorly-defined faces.
PYRITE: May occur as pyritohedrons or cubes at the Lime
Franklin quarries. Some of the pyrite cubes from the Franklin quarry
fairly large (5 mm to 1 cm). Lime Crest produces strangely elongated
crystals which appear to be drastically stretched pyritohedrons.
longest one I've seen was about 1 cm in length and 2 mm in width, but
PYROCHLORE - MICROLITE:
Suspected (by me!), though I've never had it analyzed. Overall
appearance, waxy to glassy luster, and mild radioactivity are
going on. These minerals (and euxenite, et al.), are literally
a mess to
determine. They have no definite crystal structure (i.e.,
metamict) and only full quantitative analysis can tell them
apart. Come to think of it, only certain types of instrumental
analysis are really of any use. A full quantitative chemistry
workup would be ideal, if you could obtain a large enough sample (and a
good analytical balance, along with the reagents necessary to separate
out the rare-earths).
PYRRHOTITE (Hardness: 4; Streak: black; Gravity:
4.6 to 4.7; Other: dust is magnetic)
QUARTZ: We have found no crystals yet, but tons of the massive form. Much of it is smoky quartz. Often found in "boudins" containing scapolite (meionite); the rock around the boudin is calcite (marble). Some crystals of allanite, titanite, and other minerals are locked inside quartz, making them hard to expose without breaking them.
RHODONITE: I've heard rumors of this mineral occurring
at Lime Crest.
Crystals would be rare, I'm sure. I have yet to see a piece of definite
rhodonite found at Lime Crest or any other local marble quarry. I
can understand why someone might have thought they'd found rhodonite at
Lime Crest; consider this pink mineral I
found at a Lime Crest trip (2000 or 2001):
RUTILE can occur as tiny needles, though some specimens occur in the Lime Crest rock as tabular crystals. I have one such crystal which is approximately 1.5 mm across. The Franklin quarry produces elongated rutile crystals or needles, sometimes found with margarite.
SCAPOLITE (probably MEIONITE): One of my favorite minerals... It occurs in massive form, but at least one collector found a nice crystal of it last time at Lime Crest. The crystal was a couple of centimeters long, so I'm sure you could find micromount-grade scapolite crystals if you searched enough at that quarry. Scapolite can be gray-green, light apple-green, gray, white, pinkish, yellow, or brownish. Note: most scapolite from Franklin and surrounding areas is probably meionite or an intermediate composition of meionite-marialite (with the composition slanted toward meionite). Pure, end-member marialite is fairly rare at Franklin.
SCHEELITE: I almost forgot to mention this mineral,
since I have not
found large quantities of it (yet).
SPHALERITE: Zinc sulfide. Forms brown, yellow, black, oil-green, or reddish-brown tetrahedral crystals, often sharply formed. Broken surfaces have a very high luster. There was a Mississippi Valley-Type mineralization area found in the Lime Crest Quarry which contained translucent yellow sphalerite, along with fluorite, galena, and some barite.
SPINEL: red ("ruby spinel") grading to black ("pleonaste") varieties occur at the Lime Crest Quarry. Deep purple seems to be the most frequently-encountered color of spinel here. A well-formed spinel octahedron is a real prize for a day's collecting, even if the crystal is only a couple of millimeters across. Spinel is usually translucent to nearly opaque, but exceptional ones could be transparent. It has a specific gravity of 3.5 to 4.1
THORITE: Similar to allanite in appearance when in massive form, but more radioactive. It is usually brown or black but can also be orange-red or brick red (uncommon). Thorite is of the tetragonal crystal system but can form pseudocubic crystals. It can also occur as needle-like (acicular) crystals. Thorite specimens have been found at Lime Crest. The best way to find thorite is with a radiation detector or Geiger counter. Thorite is a silicate of Th and can also contain some U.
TITANITE (SPHENE): brown, somewhat shiny, wedge-shaped
crystals up to
1 cm have been found at Lime Crest. Many nice crystals of 1 to 3 mm
there, making for some pleasing micromount specimens. The trick is not
the crystals while exposing them from matrix! They are fragile. I
90% of them break while "taking apart" a rock... maybe 95%. The
matrix is really tough stuff, a lot of quartz, so you can't just scrape
with a dental pick. Neither can you etch it away with acid. It really comes down to luck.
TOURMALINE var. DRAVITE: (Streak:
colorless; Hardness: 7 to 7.5; Gravity: 3 to 3.3; Other:
TOURMALINE var. UVITE: (Streak:
colorless; Hardness: 7 to 7.5; Gravity: 3 to 3.3; Other:
TREMOLITE: Colorless, white, gray, or bluish-gray
crystals occur in
the area quarries, often as sprays or clustered, flattened prisms. Can
massive or in grains.Sometimes this tremolite is highly fluorescent
(bluish-white SW), but much of it is not. There are some large boulder
the middle of the Franklin quarry which contain fluorescent tremolite
ZIRCON: (Streak: colorless; Hardness:
6.5 to 7.5; Gravity: 4.0 to 4.7; Cleavage: imperfect, 2
directions; Other: often fluorescent yellowish, SW; may be
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