ltpaulbtv
starting to spend too much on rocks
Member since October 2010
Posts: 198
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Post by ltpaulbtv on Jan 27, 2011 12:11:48 GMT -5
While in Long Island this summer I had a chance to check out the beach for some rocks. One of the interesting ones I found I finally had a chance to slice into slabs. It appears to be a breccias or conglomerate. Anyone have a idea what minerals it's made of? I have some basic equipment, that I use for beveling small pieces of glass, but I plan on making some cabochons. I have three diamond wheels on my edger 180g, 360g and 600g. I have a polisher with a felt wheel and cork wheel using cerium oxide and FFFF pumice. I also have diamond pads that go up to 1200g. Being my first post it has been a challenge to get the pictures posted as well, but I think I have it. I'm having a problem posting more than one picture. I should have the cabs done today I'll try to post them later. Some of my hobbies are geology, metal detecting, space, meteorites.
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Post by frane on Feb 1, 2011 15:46:02 GMT -5
That is a cool slab and the cabs turned out nice! I am really not sure what the little stones in there are but you could have some mica in there. I think I see some sparkle in there. Fran
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Post by Roller on Feb 11, 2011 21:06:27 GMT -5
nice lookin slab ... not sure what it is but it sure looks like a conglomerate to me ..
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snidley
off to a rocking start
Member since April 2011
Posts: 3
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Post by snidley on Feb 23, 2013 18:02:33 GMT -5
I've seen this sort of thing a lot on Long Island beaches. The main source I've seen for it has been human-made. There are many places along Long Island beaches where once there were roads, driveways and parking lots. In the first half of the 20th century a lot of people built beach houses out on the island to retreat to during the summer months. Roads were often made out of concrete, with large pebbles. They've since been broken up and worn down by the waves. Most conglomerates I've seen on Long Island that look similar to this are much redder, and have a high iron content. I've seen what the waves can do to a house in a storm. Long Island's North Shore is a pretty calm area overall, but when a Nor'easter or a hurricane strikes, the waves can get 15-20 feet high along the shore - and sometimes higher. I've seen concrete road slabs turned up on end after a storm has left, and there are many places where remnants of a human settlement are a ghostly reminder of how tentative the advance of human civilization on the planet truly is. The attached picture is of the remnants of the foundation of a large beach house destroyed in the 1930's in the Village of Asharoken on Long Island. Attachments:
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Post by Peruano on Feb 23, 2013 19:38:11 GMT -5
If a breccia is a bunch of broken material fused into a matrix, and a conglomerate is a bunch of rounded (i.e. transported and hence polished) material, this specimen seems to have both (some elements are obviously water rounded, but others not). The manmade origin is a possibility. You should be able to get a reaction with acid if its concrete. Bricks, pottery, tile, and yes concrete are capable of looking nice given enough wave action and finding their way into lots of our collecting buckets. But only you can tell for sure. Cheers and welcome. BTW you can post multiple photos by bouncing back and forth between where your photos are stored and the message (without closing either) or Method 2. is to post the photo, then go back to your photo source and get another and do an edit to add the second or tenth as you see fit. You can alway edit your own posts and hence they can grow but they do not jump up to the top of the page as if you added a new message to the thread. I hope this is useful. Tom
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