Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: Savanna Mehndi on 27/10/2015 13:20:58

Title: Can you please help me identify these?
Post by: Savanna Mehndi on 27/10/2015 13:20:58

DISCLAIMER: I'm new to this and don't know much about geology, especially terminology...please forgive my ignorance!  [:I]

I've recently discovered my love of rocks and crystals but I'm finding it difficult to determine what I've already collected since childhood...so I was hoping someone could help me figure out what I've got on hand while I learn more about the geology.

Also, I keep aquariums and would like to use some of my rocks as tank decorations (in both fresh and salt water) so if you know any of these as having water or salt sensitivities please include that in your response.

Location Found: Unsure, more than likely Miami, FL if not probably someplace else in Florida or Georgia.
Color(s): Black, a bit shiny.
Details: There seems to be red clay in the cracks of the rock (rust colored).
Consistency: Mostly smooth with some cracks, dents and ridges. Appears to be nonporous.
Other: Scratches easily.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi60.tinypic.com%2F241t9pc.jpg&hash=6327c9cb22c8d10691f4a85fbc377954)

Location Found: Miami, Fl inland.
Color(s): Beige, white, yellow and gray.
Details: There seems to be both shell and fossil
Consistency: The small shell is fossil while the large shell fragment is an actual shell. The backside is rigid and has a sandpaper-like texture.
Other: There is a small, brownish cube that seems to be a different substance than the rest of the rock (bottom right corner of the large shell fragment)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi58.tinypic.com%2F2ceknxf.jpg&hash=b95833d277e87d45bd42b812104ab42d) (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2F2ivmmnq.jpg&hash=2f06ec335d3bae5d3edb3145bf102b80)

Location Found: Unknown
Color(s): Gray, brown, white and off-white.
Details: There are tiny shell/sand particles within the holes
Consistency: One side is very smooth, the other is rigid.
Other: The very white area on the smooth side is powdery
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2F34qwydc.jpg&hash=4ccdf767fa50592a86c619be33dc6918) (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi61.tinypic.com%2Fqnk27m.jpg&hash=1b7c389084328e06403ad71e7453eaed) (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi59.tinypic.com%2F28t9eso.jpg&hash=b39c402353dce4d0aa40e7993218727c)

Location Found: Unknown, was a gift
Color(s): Clear, orange, brown/black and possibly yellow (may just be light reflecting off the orange lines)
Details: The clear glassy parts have a prism effect when light is reflected, bright orange inclusions and there are tiny brownish/blackish specks inside.
Consistency: Polished but there are still a few cracks.
Other: My best guess is rainbow quartz with orange inclusions.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi60.tinypic.com%2F2j6acz7.jpg&hash=9b0c99fcc67851c11579fdc72d5edba9)

Location Found: Miami, FL
Color(s): Off-white
Details: Possibly limestone? Very light, feels almost hollow.
Consistency: Looks spongy, very porous, reminds me of coral skeleton.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2Fipuruq.jpg&hash=9d2dfea4ce344d3e1a6b90049edcc58d) (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi59.tinypic.com%2F2mhwtic.jpg&hash=702c54d3f2fe20a8b0585caa3ab51831)

Location Found: On the coast of Ireland
Color(s): Black or dark gray, red clay in grooves
Details: Small, pinprick looking indentations
Consistency: Fairly smooth, slightly porous
Other: The crack down the center is from is dropping from about 5 feet
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi58.tinypic.com%2F14y0poi.jpg&hash=191f9dd9b359c339643f39b1ad2c2b11)

Location Found: Darlington, MD
Color(s): Gray, black, white and clear
Details: Mostly gray with black speckles, specks of what looks like quartz and mica
Consistency: Porous, grainy softer than quartz
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2Fwwkqwi.jpg&hash=35b6c0045ba6fcbfc45d82124756a00a)

I'm pretty sure that these next ones are mostly quartz with bits of mica but I thought I'd post them anyhow.
Location Found: Darlington, MD (mostly red clay in that area)
Color(s): White, gray, clear, orange/red, gold, brown and black
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi58.tinypic.com%2F10ye80z.jpg&hash=078aaeeb4c285ffbd088b6248f818735) (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi60.tinypic.com%2F1puyw2.jpg&hash=8c8361899a9afe6c39367f9c299910b9)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi61.tinypic.com%2Fohjz46.jpg&hash=d0db099ac76ae4d73797b129d90e08bc) (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi58.tinypic.com%2F2zzj31g.jpg&hash=0146f34d313fe966a276c04443ad124d)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi61.tinypic.com%2Fel33gg.jpg&hash=d923d21ba1c064de92b09853d0e42464)

Lastly, just for fun...I purchased this "pearl" at a flea market in the Florida Keys, the woman said it was a natural pearl but is this shape even possible to occur naturally?
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi58.tinypic.com%2F2s6rji0.jpg&hash=6316323cbfb03ca63ae0f5821de26044) (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi59.tinypic.com%2Ft707lu.jpg&hash=b67e8d276a907fc242d2f43268fcc88a)

Title: Re: Can you please help me identify these?
Post by: RD on 27/10/2015 15:23:38

I think the holes are not an original feature : holes bored into shell by another creature (https://en.wikipedia.org/wiki/Clionaidae) , i.e. holes are "trace fossils (https://en.wikipedia.org/wiki/Trace_fossil)".

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Title: Re: Can you please help me identify these?
Post by: chris on 27/10/2015 18:21:48

RD is correct on the holes; there are a range of petrophagic (stone-eating) marine organisms capable of drilling through things in this way.

Title: Re: Can you please help me identify these?
Post by: RD on 27/10/2015 19:03:50

Quote from: Savanna Mehndi on 27/10/2015 13:20:58

... Lastly, just for fun...I purchased this "pearl" at a flea market in the Florida Keys, the woman said it was a natural pearl but is this shape even possible to occur naturally? (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi58.tinypic.com%2F2s6rji0.jpg&hash=6316323cbfb03ca63ae0f5821de26044) (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi59.tinypic.com%2Ft707lu.jpg&hash=b67e8d276a907fc242d2f43268fcc88a)

I'd never seen cross-shaped pearls, but apparently they do exist but the trade-price is less than a dollar each ... http://www.aliexpress.com/item/20x35-32x43mm-Natural-Freshwater-Pearl-Cross-shape-Loose-Beads-14-5-Min-Order-is-10-we/32286394074.html

The nucleus for those pearls must be a couple of sticks, rather than a stone.

Title: Re: Can you please help me identify these?
Post by: Savanna Mehndi on 27/10/2015 22:37:16

Wow, thanks! I think I actually like that fossil more knowing that the holes were made by a living creature.


Glad to know it is an actual pearl, I was worried about that...I think I paid exactly one dollar for it, which even if I overpaid for it it's just a dollar...