Dear Rock ‘n’ Gem,
I feel sure that a reader out there who sees the letters pages may be able to offer an insight into unusual Agate forms, having a keen interest in Agates and their formation, I thought your readers may be interested to see my recent purchase. The Agate concerned is a tube agate reportedly from the Woodward Ranch in Texas, USA and it has some interesting details, an Agate is unusually formed where the banded formation is clear, but these are very different. You can see in the photograph the tubes formed within a very clear agate, this is also very 3 dimensional and more akin to the Jaspers that occur in Rhyolites, it may be that the temperature difference in the original Matrix being more silica rich produces these internal shapes.
Barry Taylor
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Dear Rock 'n' Gem Magzine,
I've recently purchased a salt lamp whilst on holiday in Europe and noticed that it seems to be 'wet'? Anewpaper placed next to it was a bit soggy when I picked it up. Can you explain what is happining is it melting or something?
Jane - Devon
Ed - one of the properties of the salt is to draw moisture from the air so if it's in a 'damp' environment, conservatory etc. it could be soaking up the water. Best solution is to pop it somewhere warm for a day or two, perhaps the airing cupboard.
Hi RocknGem Magazine,
Thanks for the new mag – thought it was very good – getting much more readable these days. I was interested in your reply to the query on encouraging children/young people interested in rocks, minerals and fossils. You did not mention ‘Rock Watch’.It is regionally organised with talks, field trips and a regular magazine. Last time I checked it was about £15 per annum. Afriend of ours introduced her granddaughter to it and was very impressed It has a good website.
ROCKWATCH - the club for young geologists - HYPERLINK
http://www.rockwatch.org.uk" www.rockwatch.org.uk
Janet
Dear Rock n gem
I have regular communications with your frequent letter writer J Jocelyn who like me is an Agate fan. He wanted me to send the attached photograph of mine (A) picturing a classic tube of escape, this portrays a tube from a Pirhna Agate from Brazil which has the classic orange colouration of this variety. You can see the pressure dilation process that has occurred in the tube, crystallisation results in excess fluid which is then expelled from the same tube and banding in the process of formation is distorted. The centre of this Agate would have been filled with the remaining silica rich fluid with an altered chemical balance and as Quartz has a slightly different density structure from Chalcedony this results in a pressure imbalance. I wish to point out that there are several other equally important descriptions relevant to this complicated mechanism and in the attach photograph (B) a tube of entry-exit has occurred where the fluids of formation have acted in a rhythmic process, this agate has the typical cream-green colour of the Condor agates. You can see that the tube has been distorted and that another formation scenario has played out, here movement must have occurred in both directions, possibly brought about by a pressure differential, created either by deep burial of the host rock or a later heat reactivation process.
In photograph (C) you can see a further complication where the dilation has been filled with a secondary localised banded agate in another Condor Agate from Entre Ramos. Finally in (C) a Brazilian Agate with classic black banding has a dilation in the middle of the agate rather than the usual outer level, all of these structures are certainly worth investigation so please send in any photographs you have.
Barry Taylor
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