Lapidaryforum.net
Let's Rock => Rock Talk => Topic started by: Rustycat on September 27, 2018, 11:14:14 PM
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Found this rock on the beach, the green is quite brilliant, looking forward to cutting it for a better view. Jadeite?
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Have you tested for hardness? It looks rather rough on the surface and I would think that a jadeite in a beach environment would show a much smoother and polished surface due to it's hardness and toughness in a rather abrasive location like the beach. Hope that it is for you but I question the surface shown
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irock,
It doesn't scratch by a pocket knife. Well, the rind scratches, but the green core doesn't. I've not seen any other rocks that are similar in their resistance to being worn down, which made me think it was unusually hard. Here's a more usual beach rock, that I picked at the same time, hopefully the red will develop when it is cut
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Listwanite , typical listwanite.
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lithic,
Thanks for sharing your expertise, it is greatly appreciated.
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I did a short search on listwanite and found the following thread on mindat to be helpful : https://www.mindat.org/forum.php?read,11,397394,397401
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The piece on that mindat post looks nothing like any jade in Washington but it again is typical listwanite. The amount of jadeite in Washington is vanishingly small.You can barely find it near the remote outcrop where it is in situ. Nephrite may not have a skin , an oxidation rind in about one piece out of 5 thousand.That is 40 years of finding hundreds of thousands of pieces talking.Listwanite is actually quite interesting and like many rocks there used to be much more info on the net about it.Much of the good rock identifying info on the net started to disappear about 7 years ago and now it is virtually useless. some of this is due to search engine design but most is because legitimate sources have been attacked over and over for not going along with accepted rock hound " wisdom " or by folks wanting to market the stone as something new with remarkable powers.Why bother hosting a page that causes grief. Listwanite was a carbonate in a fault which ha been injected with fluids. This process can repeat as long as the fault is active and there are hydrothermal fluids available. The end stages which are very rare are a red version which is sold on ebay at times and a uniform powder blue silica which is way too rare for ebay.The version you have is typical in that the green blebs standing proud are fibrous calcedony.As it is exposed the surface calcedony is often a different color than in the interior due to being a different oxidation state.when you find blue blebs on the surface they will be green inside.The calcedony is never big enough to cut as cabs or even beads but it can look good in whole listwanite cabs.It usually undercuts due to the carbonate content.The grooves on the outside of your piece are due to differential weathering and some are surely due to the weathering of calcite.Next to Mt. Vernon there is a mountain of this grade listwanite in the Darrington -Devil's mountain fault zone. It has at least 4 ,000 feet of tunnels from prospecting work that wrapped up in about 1914.Virtually no gold but about 1% mercury in large amounts of it. It is normally a gold ore such as in Atlin because it is brittle and crushes easily so that mineral bearing fluids can easily penetrate it.The mother lode in the Golden state is also an example. Our nephrite has an oxidation rind and is virtually always smooth and on the beach typically eliptical in shape
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lithic,
Again, thank you for being a willing and knowledgeable resource, for those of us trying to learn about the rock and mineral resources available in the Puget Sound area. I certainly enjoy my time cobble crawling along the beach on Vashon, and have certainly found a number of interesting (and somewhat confusing specimens) since I recently became interested in looking at the treasures under my feet. On the trip I picked this piece up, I thought I'd carry my coho rod outfitted with a buzz bomb and try and pick up a salmon or two, but, alas, the only thing I learned is I couldn't watch the water waiting for a jumper and look for rocks at the same time.
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And, since everyone enjoys looking at rocks, here's one more off the beach.
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Very bad coho year.The big native coho tend to come through in October in one very quick push accompanied by orca's.I have seen them jumping all the way across Admiralty Inlet using binoculars, that is orcas and salmon.Ocean conditions may preclude us ever seeing that again.Good luck .