sorry if i misdirected my response… have a nice day.
to answer your question: sphalerite is face centered cubic… it will take forms other than a cube with regular sides…all belonging to the cubic family of crystal structure. Diospide by contrast is monoclinic. It is a pyroxene mineral with a variable composition. Diopside is very common in metamorphic and igneous rocks. Sphalerite will occur only in association with other ore minerals. Gangue associate minerals include fluorite, barite. calcite.
I have confirmed calcite, native copper, iron, galena, magnesium, pyrite, quartz, gold flakes, limonite after pyrite, copper after cuprite malachite, azurite hematite, magnitite, large mica, large crystal clear feldspar, serpentine, and garnet in mica schist… this material is irregular and perfect cubes its in blue light and dark green (every shade) brownish red, black, silver,white colorless, yellow, all beautifully transparent i also have red pink and purple still to be tested, it shines beautifully floreses in short wave everyone says it looks like glass until they touch it then everyone says thats not glass. It sounds different from glass and is cold to the touch.
I also have unconfirmed 1 suspected meteorite and 1 possible platinum sample, 1 possible emerald
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very good. you have a sample from a highly mineralized zone. The assemblage of minerals is typical for a hydrothermal vein, hosted by a mafic metamorphic rock especially if serpentinite is present.
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I am able to confirm that I have hige grade metamorphic rock including garnet muscovite schist an gnnice with crystals zebra marble and so on so is my quartz possibly tridymite?
possibly but very not likely. the reason being is that if the metamorphic rock cooled slowly, high temperature phases of quartz would revert to alpha quartz. Another reason is that the field for Tridymite and cristobalite is at low pressures, not within the field of metamorphic rock high pressures, which is why it is usually found in gas cavities within rhyolite… the temperature is hot enough for cristobalite formation. The rhyolite flows will cool faster and to “lock in” the high temperature phases. Google the phase diagram for silica. You will see that both tridymite and cristobalite comprise a very small area within the phase diagram at low pressures…I think that if you just google the silica phase diagram, you will understand why high temperature forms of quartz are rare. You can also see that as the pressure increases, the higher pressure forms of silica become dominant.
Wow Steven! Looks like you are living proof that degrees aren’t necessarily a direct correlation to someone’s knowledge on a subject. Very cool to see. Though, I support you getting a Geology Degree for fun now that you’re retired. 
Where are you located? I’m near LA, would love to network with you as I’m a GIA newbie.
Cheers!
-Merritt
I am located in the Black Hills area of South Dakota but am relocating to a warmer place… Albuquerque NM. I was interested in rocks and collecting them since I was a kid… My home land of origin is Honolulu, HI… as I kid I read about volcanology as applies to the active volcanoes on the Big Island, I started memorizing the stoichiometric formulae of common minerals from Dana’s Mineralogy, crystal classes… none of those minerals with the exception of a very few were found on the Hawaiian Islands. Fosteritic periodots occur in the lavas of the islands but none are large enough to cut… they are quite gemmy even in matrix. Everything else consists of pyroxenes and plagioclase feldspar. I took a jewelry making class in high school and learned the basics. I have contributed to the sister website Ganoksin on many topic based on my experience as amateur jewelry fabricator. I do have a doctorate degree but not in engineering or the physical sciences. My area of professional expertise is technical and can be mathematically involved… I have never lost my interest in science. I am well versed in basic physics and chemistry, which is why I can comment (with constant fact checking) on the science behind rocks and minerals… I took my own deeper dive into geochemistry, after having studied geology as a layman throughout my life. I attended the last two annual Goldschmidt meetings of the Geochemical Society. A friend of mine who has a PhD in geology and geochemistry thought that most of it would be over my head… I found that I was able to conceptually, although not quantitatively,understand most of the current research in the field… I had previous read several 300 and 400 level textbooks on geochemistry and petrology… also a book on isotopes covering Nd/Sm, Rb/Sr, Uranium/lead ratios and K/Ar dating methods. It helps having a some basic knowledge of thermodynamics, including phase changes, and some basic mathematical tools such as differential equations which are aspects of chemistry. These topics are ones I have to return to repeatedly. However, all of the knowledge of the world is at your fingertips thru the internet. You just have to know what to look for.
I joined this website because I have a large number of gemstones that I have not been able to set into jewelry and were purchased 25 years ago. Some have gone up ten fold in value. I intend to sell them, along with jewelry making tools and precious metals as part of downsizing. I no longer have an interest in gems per se but am more interested in mineral paragenesis and the processes that created them… If I seem knowledgeable about these processes, I still could very well be wrong and would like to have another professional call me out… fact checking is imperative.
Im able to confirm high temperature and high pressure and lots of Quartzite sedimentary metamorphic magnesium copper and iron
Quartzite is a metasedimentary rock originally composed mostly of sandstone… it is stable across a wide range of PT conditions. minerals that originally cemented the sandstone together get incorporated into the quartzite… red sandstones contain hematite which is ferric iron oxide… yellow and white sandstones can be cemented by calcite, dolomite or other magnesian sedimentary minerals. low grade metamorphism will incorporate some of these cations within the quartzite as new minerals. metamorphism however does mobilize ions. most quartzites are nearly pure quartz. they have very few accessory minerals. By some definitions, it must contain a minimum of 80% quartz. Most have a higher quartz content. metamorphism mobilizes pore fluids, mostly water… the water is driven out as the rock changes and recrystallizes from sand grains. cations are mobilized by the water and are basically washed out… that’s too simplistic an explanation but does serve the purpose. Mobilization of pore fluids does have a secondary effect…cations that are mobilized have to go somewhere. That somewhere can be in shear zones and faults that become mineralized with metallic elements and form ore deposits. metamorphic rock hosted gold deposits are just one example. Copper is much more abundant than gold and also will be deposited in ores…quartzite once formed is extremely resistant to weathering and erosion…more susceptible rocks will erode away, leaving quartzite ridges. Look up quartzite on Wikipedia for a start…
I have native copper and gold. More copper than gold for now because i find the copper in larger peices and the gold is either in quartz or small flakes in my flower beds. I also have the high grade metamorphic rock so …
I’m not new to science i read tons of books on geology but sometimes a lack oh a person who is able to look at it with. Someone who sees me do all my tests and experiments… leads me into a quandary where i doubt myself. I have been studying earth science with a passion for over 30 years but till recently geology was not a topic i had explored.
read about mineral paragenesis in copper and gold deposits… it’s quite different for gold and copper. You learn more if you look it up yourself than if I told you… everything can be found on the internet… hit on science direct or ResearchGate when you find promising articles.
I don’t think you understand what I am saying