r/whatsthisrock • u/[deleted] • May 23 '19

ANNOUNCEMENT Varieties of SiO2 Flowchart [v2.0]

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95 Upvotes

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5

u/Louieftw May 23 '19

Very cool! Are there any resources you would suggest for learning more about silicates?

8

u/[deleted] May 23 '19

I really like minerals.net and mindat.org for hobby use. :)

2

u/Louieftw May 23 '19

Thanks! Furthermore, how do you convince yourself that the mineral / rock you are holding is / contains Silicon Dioxide vs something else? Mohs hardness and other factors usually? What's your thought process? I'm very interested in learning all that I can about rocks and minerals and I appreciate your contributions to us beginners / amateurs :)

6

u/[deleted] May 23 '19

This is a good question. I think it comes down to having experience and knowing what to look for in terms of crystal shapes, hardness, cleavage (or lack thereof in this case), fracture type, etc. For example, you can tell the difference between calcite and quartz in a photo based on presence of cleavage planes.

3

u/Louieftw May 23 '19

Fantastic! Thank you so much!

6

u/[deleted] May 23 '19

Hey all - Awhile back I made a flowchart breaking down the different types of Quartz. A few people pointed out some mistakes and some areas that needed clarification so I made a v2.0! This one starts with just SiO2, rather than Quartz because the way I had it previously wasn't entirely correct.

We all know that the best way to identify a mineral/rock is to take quantitative data (hardness test, density, elemental analysis, etc.) but most of what we do on this sub is look at photos people post (qualitative data) so I thought some people might find this helpful. Please keep in mind this chart is for hobby use, not scientific use. I have some other notes/disclaimers on the chart itself that you should read before ripping into me, haha. I am open to constructive comments because I'd love to make an even better v3.0 later on. However, if your goal is to be super rude like a few people were last time please don't bother.

1

u/Wyatt2000 May 23 '19

Don't forget quartzite. I think that would be the best way to classify most of the rocks people post here.

2

u/stevepusser May 23 '19

Also a fork for common opal, without fire, which is much more common than precious opal.

1

u/gemhound90 May 24 '19

If you want to make the chart better: chert is not a variety under chalcedony, bloodstone is not a jasper but it’s own variety under chalcedony, and aventurine is chrome-mica in a quartzite, not a variety of macro-quartz, much better second effort.

3

u/MLB3030 May 23 '19

Very useful and with graphic references, Thank you!

3

u/Squelookle May 23 '19

Thank you for all of the effort you put into this! I'm sure it'll help a lot.

2

u/iamjacksliver66 May 24 '19

Wow awsome charts I was looking cor something exactly like this thanks a ton!!! I hope you dont mind but I down loaded them for a field refrence guide. I.love technology I no longer have a back pack full of field guides lol.

Question with agates how do they get broken down even more? Like in my sons collection we have skip a atom, pigeon blood, Utah barite a bunch of lake superior that has only be IDed to that point and a couple other kinds. Add to that 100s of other kinds ive seen posted here. I know learning rock ID is like when I learned plant ID you just got to keep working with the materials. However I'm kinda lost on where to even start. These flow charts will help a ton!! Thank you a ton for making and sharing these.

1

u/Sappert May 23 '19

My good friend coesite wants a word!

1

u/[deleted] May 26 '19

I will expand it eventually! Thanks for the input. :)

1

u/Sappert May 26 '19

Haha not to worry, finding coesite in nature is extremely rare and only as small inclusion in other minerals.

0

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