![]() ![]() These sand inclusions sometimes form hourglass formations in a crystal. ![]() Gypsum sometimes forms in sandy areas, and crystals may trap sand inside when forming, causing a specimen to become brown or gray and opaque. Such specimens are considered a mineralogical oddity, and are very desirable to collectors. When such a crystal is rotated, a water "bubble" moves around inside it toward the lowest point in the channel. ![]() In a small number of Gypsum specimens, water gets trapped inside a crystal in a hollow channel while the crystal forms. Some Gypsum specimens show evidence of this, containing growths of crumpling layers that testify to their expansion from the addition of water. Many Anhydrite specimens absorb water, transforming into the more common Gypsum. Gypsum has the same chemical composition as the mineral Anhydrite, but contains water in its structure, which Anhydrite lacks. (Though trying to bend good crystals is not recommended, as their flexibility is weak, and if flexed too much they will break.) Gypsum crystals are known for their flexibility, and slim crystals can be slightly bent. Such crystals are found in a clay beds as floater crystals, where they fully form without being attached to a matrix. Many Gypsum crystals are found perfectly intact without distortions or parts broken off. like Jello different conditions & contaminants can cause inconsistances in test results.Gypsum has many interesting properties, including its very unique crystal habits. Also, as you gain experience, you'll soon see that many properties are totally firm. As you noticed, "hey, i am learning items " to "now wishing the "real" information was out there that include chemistry", I'd say look closely at the publishing dates of the books you are reading & to assume that some NON-technical terms & substances may have changed meaning since publishing, & to study a LITTLE chemistry, so you have an idea what you're dealing with. The best thing that has happened is you've connected with this site, but, to tell the truth, I was you had someone who was experienced, standing over your shoulder, as you were doing these tests.ĭon't get me wrong, you NEED to do tests & you NEED to ask questions but, before you do tests, you need to ask how to do them & under what conditions. Also, Rob is 100% correct, some things are left out bcs amateurs, with no experience, can get permanently harmed or killed, doing things "fly-by-night" you not knowing that: A) the rose quartx xls weren't, B) that there's a difference in reactions between sulfuric & HCl, & C) what the possible reaction products could be all point to dangerous inexperience. The guides were accurate & useful by their publishing date's standards, so, they were correct you not knowing that the nature of vinegar had changed, isn't the guides' fault or even yours, it's one of those things you find out as you go. Understand that the manuals that suggested using vinegar as a substitute did so BEFORE the 70's, which is when vinegar in the US was cut from 15% acidity to 10% to make matters worse, within the last 10 yrs, the acidity was cut further, to 5% max. too easily.Ģ6th May 2009 21:18 UTC steven garza Dear Rex is a very poor tool, for ID, in most cases too much of an activator, as well as too little, can shut off a specimens fl. ![]() A mild reaction, in sulfuric, would point to calcite, bcs, it'll continue to bubble slowly, despite the forming coating, only bcs it's so much more reactive to acids.Īfter fully dissolving the "X" in the HCl, UNDER AN EXHAUSTING VAPOR HOOD, put a single drip of sulfuric in the solution & see how much calcium sulfate "snow" forms in the tube if a lot forms, it's calcite, if some forms, it's dolomite, if VERY little forms, its rhodocrosite. Re-try the experiment, using a DIFFERENT chip & the right acid & give us the results. That super-thin coating will slow the reaction to a near crawl, making your observable results appear nothing is happening. Recent Images in DiscussionsĢ6th May 2009 13:32 UTC steven garza Dear Rex īy dropping it into sulfuric, instead of HCL, like you said you were going to do, you've change the results you should have gotten the fizzing may not occur, hardly at all, bcs, if it's dolomite or calcite, the immediate reaction is to produce a LITTLE CO 2 & much slower dissolving calcium hydrated sulfate (gypsum - CaSO 4). Currier Digital LibraryOpen discussion area. Techniques for CollectorsOpen discussion area. Minerals and MuseumsOpen discussion area. Mineralogical ClassificationOpen discussion area. Lost and Stolen SpecimensOpen discussion area. ╳Discussions □ Home □ Search □ Latest Groups EducationOpen discussion area. ![]()
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