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Gemstones, Minerals & Fossils
Gemstones and Minerals
❓Your Mineral Identification Questions answered here
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<blockquote data-quote="user 4386" data-source="post: 391243" data-attributes="member: 4386"><p>Beryl (aquamarine) is harder than quartz, Coin doesn't have to be sharp. if softer it will leave a smear of metal on the sample. Chalcedony is much the same hardness as quartz - its correct mineralogical name is microquartz (so just very fine-grained quartz) - not the same as opal which is a different mineral.</p><p>Fluorite (sometimes clear) seems unlikely (can be clear but not rhombohedral shape) - apatite colour wrong and rarely shows cleavage. Things like dolomite and mmagnesite are harder than calcite (especially magnesite) but I rarely see those carbonates as transparent crystals (but can occur):</p><p></p><p><a href="https://www.google.com.au/search?q=magnesite+crystals+photos&client=firefox-b-ab&dcr=0&tbm=isch&source=iu&ictx=1&fir=I1RVDjHeoNbmUM%253A%252CgUt7Dhm3_7odSM%252C_&usg=__JujbDm4c61lTSsmQMEGMLX-frgY%3D&sa=X&ved=0ahUKEwiHzOCL1bjZAhXGX5QKHXPAD2UQ9QEIPTAK#imgrc=I1RVDjHeoNbmUM" target="_blank">https://www.google.com.au/search?q=magnesite+crystals+photos&client=firefox-b-ab&dcr=0&tbm=isch&source=iu&ictx=1&fir=I1RVDjHeoNbmUM%3A%2CgUt7Dhm3_7odSM%2C_&usg=__JujbDm4c61lTSsmQMEGMLX-frgY=&sa=X&ved=0ahUKEwiHzOCL1bjZAhXGX5QKHXPAD2UQ9QEIPTAK#imgrc=I1RVDjHeoNbmUM</a>:</p><p></p><p>Magnesite can be as hard as 4.5 - so a possibility. It reacts with hot dilute hydrochloric acid (but neglibly with cold acid, unlike calcite and to a lesser extent dolomite). If you powder some finely and drop powder into a candle flame. the flame should go bright white.</p><p></p><p><a href="https://geology.com/store/collections/" target="_blank">https://geology.com/store/collections/</a></p></blockquote><p></p>
[QUOTE="user 4386, post: 391243, member: 4386"] Beryl (aquamarine) is harder than quartz, Coin doesn't have to be sharp. if softer it will leave a smear of metal on the sample. Chalcedony is much the same hardness as quartz - its correct mineralogical name is microquartz (so just very fine-grained quartz) - not the same as opal which is a different mineral. Fluorite (sometimes clear) seems unlikely (can be clear but not rhombohedral shape) - apatite colour wrong and rarely shows cleavage. Things like dolomite and mmagnesite are harder than calcite (especially magnesite) but I rarely see those carbonates as transparent crystals (but can occur): [url]https://www.google.com.au/search?q=magnesite+crystals+photos&client=firefox-b-ab&dcr=0&tbm=isch&source=iu&ictx=1&fir=I1RVDjHeoNbmUM%253A%252CgUt7Dhm3_7odSM%252C_&usg=__JujbDm4c61lTSsmQMEGMLX-frgY%3D&sa=X&ved=0ahUKEwiHzOCL1bjZAhXGX5QKHXPAD2UQ9QEIPTAK#imgrc=I1RVDjHeoNbmUM[/url]: Magnesite can be as hard as 4.5 - so a possibility. It reacts with hot dilute hydrochloric acid (but neglibly with cold acid, unlike calcite and to a lesser extent dolomite). If you powder some finely and drop powder into a candle flame. the flame should go bright white. [url]https://geology.com/store/collections/[/url] [/QUOTE]
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Gemstones, Minerals & Fossils
Gemstones and Minerals
❓Your Mineral Identification Questions answered here
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