Identifying Igneous Rocks -- Earth Rocks!

For an introductory college-level physical geology class: a review of how to classify and identify an igneous rock. Includes a discussion of the compositions ultramafic, mafic, intermediate, and felsic; and the textures phaneritic, aphanitic, glassy, frothy, pyroclastic; also reviews the naming process for porphyries and pegmatites, including identifying and naming the phenocrysts (and sorting out all these different terms!). Covers the following rocks: peridotite, gabbro, diorite, granite, basalt, andesite, rhyolite, obsidian, scoria, pumice, and volcanic tuff.
**This video comes near the middle of the semester, so there may be terms with which the audience is unfamiliar. For a full playlist, refer to the Geology playlists on the Earth Rocks! KZbin Channel.
Content within this video is based on information available in any standard introductory college geology textbook (or lab manual), such as Essentials of Geology -- Tarbuck and Lutgens -- Pearson Publishing.
If you are an earth science enthusiast and would like to support our ongoing video development and engage with us behind the scenes...
Or if you are a student and would like access to interactive lessons built around these videos...
you can do so by JOINING the Earth Rocks! KZbin Channel:
/ @earthrocks .
Thank you!

[@mwilson14]

This is one of those KZbin videos I need to watch repeatedly to better understand the minerals I often misidentify.

[@Nothingimportant1]

After six years again a geology class, who knew it comes back to me. I loved rocks and minerals, but the college, prof we studies, led us to abhor it even. Now, understanding English and having access to KZbin, makes me interested again. Thank you for such a great video.

[@brento2890]

Excellent explanation. Best video I have seen on KZbin so far. I've only studied geology as a hobby (for about ten years). Although I have a degree in biochemistry, now I'm going to take a geology class at a local community college. Thank you! Keep putting inspirational videos online!!!

[@AbdulJalil-ry7qr]

Best explanation

[@elathiaskade7311]

19:14 That is a quality visual arrangement, very logically organized. I really appreciate it. Production quality is pretty nice, like that well-done cut to show the floating Pumice chunk in a bucket.

[@nancypatino7739]

Excellent explanation. Your voice and the pictures are the perfect mix to learn

[@bigboizism]

Skip classes, watch a 15 min KZbin video once a week, get a 90 in the course ah

[@shandevin5417]

pretty easy to do when taking these easy ass general ed classes. static engineering and calculus 3 on the other hand is more like go to class and come home and study 4 hours after every day to get a b or c

[@gregglira9947]

@@shandevin5417 Geology is not a general ed class, and the advance geology courses can get harder like math or any other science!

[@MooMooMath]

Great video. I can appreciate the research and work you guys put into this video.

[@bingluo7503]

The video is more better than some textbooks. It's helpful!

[@Hartcore11]

This video is helps greatly in understanding what I'm seeing in my river trips in the mountains.

[@alvaromorales6828]

Good explanatory , keep doing these practical videos.

[@StereoSpace]

Awesome explanatory video. Thank you.

[@jeromejeitany3277]

Amazing !!! informative,blunt,logical!

[@nunyabiznes4471]

This was excellent. I took a geology class in college, and I love rocks, minerals and fossils. I’m still confused on a lot of it, and this video certainly helped mitigate the confusion of where, how processes occur to result in which deposits. Thank you for an outstanding presentation without unnecessary words.

[@EarthRocks]

Glad it was helpful!

[@jant232000]

THANK YOU!!! I have been so frustrated with my geology class. This will save my butt for midterms

[@anastaziuscyriacus5415]

this video helped me a lot with my Earth material UE exam, God bless you

[@marcgradycole3523]

Thank you, for this and your tremendous series of videos/lessons. I only wished my geology professor's lessons were half as effective as yours. Your students are lucky to have such a talented professor like you.

[@ianhubbard4954]

I only just became interested in rocks. I bought a few now that don't originally come from England. I just find interesting to wonder how many millions of years old it is and all the what ifs. Thanks for the video I'm hoping when I learn the basics the video will be a huge resource

[@radekgalabov9638]

This was SO helpful! Thank you!

[@qpuej]

best explanation so far!! greets from the world

[@ErrolMiller-ey3lb]

EXCELLENT PRESENTATION. INFORMATION CLEAR. THANKS.

[@reneespiricueta3543]

Great information. Easy to understand thank you for sharing this information

[@kryztyn127]

Thanks! This helped on my granite/ diorite problem

[@kaeligrace]

Thank you for this! My geology class is so interesting but so fast paced that it’s hard to learn and appreciate anything before a new subject starts. This was explained in such a clear way and I feel much less stress about my upcoming tests!

[@EarthRocks]

Terrific! Thanks for sharing that. :)

[@colette8507]

Pretty Good Diet Granola BAR (no matter how bad a mnemonic you think it may be) is probably going to save me in my Geology prac exam for uni tomorrow. Thank you so much

[@prestongallimore]

I'm going to live in the woods so i need to learn this

[@literature.lover123]

Me too

[@joanofarkhuakau4154]

You still in the woods

[@FilhoDoFogoEterno]

i am from brazil, good luck. are you alive? lol kkkkkkkk

[@lindadechiazza2924]

I think you are planning to live in a rock quarry not, not among trees in a forest...please dress accordingly

[@AthensGreec]

Thank you so much for this video!! It was really helpful!

[@rhadicalmaindz]

Awesome work.

[@sarielizard1]

god bless you!!! so much awesome!!!

[@angelic2234]

Brilliant, thank you!

[@lowcyzlota]

The best explanation ever!

[@theultimategamer384]

I have science test tomorrow 😥and this made me confident and ready for the test😌thnx :) 😘😘

[@terrisweet4632]

Wow, this is the best video ever! 🌟 🌟 🌟 🌟 🌟

[@GeologiadaTerra]

such a great video! thanks!

[@eliphillips2475]

best explanation of bowens reaction series better than my instructor

[@domotushi1483]

could you send me a link?

[@salmanshai9150]

Excellent!

[@Yooitsblake]

This woman helped so much. Great video and explanations. you deserve a million views.

[@petertolibas648]

Thank you very much Earth Rocks, I'll come back if I ace my exam :D

[@allisonfu9503]

Pretty Good Diet Granola BAR, hope it will help me with the Geology lab test!!!!!

[@sunilkumar-nj4zt]

Crystal clear .

[@surajpatel3044]

Thank you so much ma'am for this ultra helpful video👏👏👏🙇🙇

[@nicolabrailsford8361]

This video was very helpful as iam trying to learn all about rocks& minerals

[@dipendraadhikari3710]

Excellent explation and visualization...as i am the student of Geology from Tribhuvan University ( Nepal)

[@007shubhs7]

very awesome your voice and your bowmen series

[@DineshSingh-hk3te]

Very good presentation

[@jeffreyallen3796]

Thank you!!

[@pratyakshya.psahoo1611]

Thanks for this video..☺

[@teneoaristocrata3270]

Very helpful. Than you so much!

[@asifmehsud7018]

wow. Amazing explanation . i was never expecting that I will learn about igneous rock so easy as I do through this video.

[@kamaldeshmukh66]

really a good explanation..helped me alot in knowing some of the basic concepts of geology.

[@joaoaox5485]

very good, thanks

[@wouldhave4998]

Now i can play Dwarf Fortress with some nerdy background info!

[@nadiasourez8560]

Hi, thank you.well done

[@abdirahmansaid6392]

We like how u decribe this lesson thanks

[@pratibha2125]

Good best explained from everyone

[@jemalsd8877]

Thank you so much

[@SkalaMustafa]

Very organized (Y) informtive

[@thegodofwar3756]

Loved it really

[@Saint.questions]

This is my class! :)

[@haseo8244]

That's why mt st. Helen had a lot of ash high silica content while Hawaii is basically based on basalt.

[@ckmo8542]

this is an amazing lecture, it;s so helpful for me!

[@emmanuelagustusmondilla6468]

Thank you!! I wish you're my teacher in Petrology.

[@EarthRocks]

Aw shucks. Thanks. :)

[@sophie20001]

great!

[@fortheearth]

Wonderful video! Thanks for sharing.

[@dominickrusso99]

Good job I like a couple bars 👍

[@meilani-2163]

COOL!

[@roniidica8482]

Thanks...

[@sarahr.6520]

I figured out a mnemonic you can use, i just invented from watching this video; 'Please Go Dumbledore, Go Back And Read' Hope it can help :)

[@mikestevens8012]

I like your precision's. 4000 ,new semi earth like planets found ( numbers vary ) . I like rare metiorites , I think we over looked the nature of 2-3% of metiorite samples . Fusion crusts , to compare an contrast , chondrules , " thumbprints" specific minerals and combos ...I need field tests and can you recommend , or make , a resource.?.

[@lindadechiazza2924]

Mike, Moissanite can you dig it?

[@nandanajihhabibilafif4631]

Gracias

[@ananyabanerjee5814]

This is awsm

[@HoboMinerals]

So, how large is unusually large for the crystals to be?

[@ismaleali6076]

No words exdpres for some one updating my proffishional carrier.G.I.Ali

[@haseo8244]

Large crystals can be granite. Small crystals are basalt and rhyolite. But rhyolite are not the easiest to Id.

[@rastkoglisic4358]

What would happen if during the magma 's cooling and travel, the starting minerals are not removed?

[@EarthRocks]

Then it would produce an ultramafic/mafic intrusive (peridotite/gabbro). Likely the minerals would all be zoned, with rims of a more evolved composition than the cores. For example, the plagioclase crystals would be zoned, with calcium-rich centers and more sodic rich as you move away from the cores.

[@jaczad6329]

hi, just found a hard round greyish rock covered with somehow looks like rusted rock.I really want to know what this is, please comment if you know. thanks

[@EarthRocks]

I'm pretty good at rock ID, but usually at least with a picture! ;) The round nature of the rock just means it was eroded by rolling around in water (waves or river). Hard and grey could be a sedimentary rock, like mudstone, or a volcanic rock, like andesite. The rusty edge is probably just that, rusted out surface where chemical weathering has left rust deposits on the surface probably from reactions with iron in the rock. Attach a good picture, I can do a bit better!

[@ant5908]

Ty

[@warriorwoman1719]

This is great. Thank you for posting!!!

[@haseo8244]

Another clue is if a rock is unusually heavy it have high metal contents.

[@davidladu7159]

You are an iron lady! Thank you very much :)

[@VolcanoSunriseSunsetEruptions]

I need your help! I am watching the volcano in Iceland and I am seeing so very strange colored lava! The color runs thru the lava so is not a reflection. I have seen pink, blue, white, green, yellow, red, silver and PURPLE lava from this volcano. I very much would love to know what the compositions would be? I am not seeing these colors covered in your video. I read that this volcano is changing from Mafic to Tholeiitic flow from the Moho region of the mantle? I sure could use your expertise. I have been researching for weeks and no one knows the answer. I have photos I could share with you. Thank you so very much! I understand the yellow lava could be Hornblende? and maybe Feldspar Rhyolite for the pink? Maybe Titanium for the white lava? No matter what I cant find a single chart that talks about Purple, blue and silver lava!! Helllllp! Can a volcano go back and forth from being Mafic to Tholeiitic? If I understand your video the colors depend on the type of lava flow it is?

[@lindadechiazza2924]

Kimberly i am fascinated by Indonesia Ijen volcano witn blueish gas lava and as you know Aurora borealis different colors are maybe account of the various elements composition so you are on to something. . ..

[@clairekarin9668]

godbless you madam

[@abdourahamaneguisse7864]

fantastic

[@mineralstones5161]

what about kimberlite

[@jannalreybalondo7555]

I have aphanitic granite 12 to 15kls.

[@mineralstones5161]

why you dont tall about daimonds ?

[@geoffgeoff143]

Simply define texture and composition.

[@stephenfennell]

Could you do the same video again but with several seconds pause after each sentence to give us time to digest what you've just said? The talk is good but every sentence contains so many facts (all of them new to me) that I cannot absorb them before you're onto the next sentence and more facts. I need time to look at the picture and think what you've said, so the facts can crystallise in my brain, like magma cooling nice and slowly underground into large crystals. Thank you!

[@katrynwiese190]

Thanks for the feedback. Everyone processes information at different speeds, so thank goodness for video that you can pause and rewind!! That's the best I can do. I totally agree that it's great to look at the picture and think about what I've said. But my videos are designed to pack in a lot and depend on the pause and rewind button to accommodate time to think. It would be WAY too long a video otherwise. Still a great idea!!! :)

[@nhlakaniphosikhosana6927]

Thank you! I benefited a lot from this video. I thank God for letting me find and watch this video,without Him I probably would not have found it and don't know what I would do. God bless this channel and the videos you make. May you carry on to help many through these videos and more initiatives that this organisation is involved in. May the Lord, Jesus help you and reveal Himself to you and may God, our Father, give you His Spirit; and may His Spirit lead you in His ways. Amen.

[@thebestofallworlds187]

why does water make the viscosity lower? 2:42?

[@EarthRocks]

In general, the viscosity of a liquid comes from how much the molecules in the liquid stick to each other. The more they try to bond (like they will fully when solid), the more viscous the liquid. In magmas, more than 50% of the molecules are SiO4(2+) -- silicon-oxygen tetrahedrons. And these like to stick to each other. The higher the % of Silica, the stickier they are. When water gets into the magma, the water molecules surround the silica tetrahedra (attracted to the charges) and interfere with its ability to stick to itself. So the liquid becomes less viscous. Same thing with syrup. Sugar molecules like to form weak bonds in the liquid (en route to full bonding when solid), and when you add water, you break some of those bonds. Make sense?

[@thebestofallworlds187]

Yeah, that is perfect. thank you for taking the time to describe this.

[@davidbrehmer2596]

I can't tell the difference between the aphanitic with crystals embedded in the matrix and the typical phaneritic specimens.

[@EarthRocks]

*Aphanitic with crystals embedded in a matrix = the porphyritic variety of aphanitic. The crystals you can see are called phenocrysts, and typically they will have perfect shapes/edges as they were carried by the erupting magma to the surface and then the lava solidified around them. *Phaneritic = 100% intergrown visible crystals. Typically the crystals will be similarly sized and intergrown. It can sometimes be hard to tell if there are a LOT of phenocrysts in your aphanitic rock (like a hearty stew). Looking through a handless or a thin section of the rock will help.

[@davidbrehmer2596]

@@EarthRocks Thanks. It's probably easier to tell in person.

[@FurryCombatWombat]

Who else is here cramming before Science Bowl?

[@JoseLuna-iu6jw]

I have a ultramafic rock dark green white black rock

[@pure4dsr817]

Who wants the Job to-put- it together

[@edthoreum7625]

5:16 chart

[@melanie19524]

13:23

[@michiganmitten1147]

Forgot about porphyry rocks

[@haseo8244]

Hmmm remember that tuff can also be pumice.

[@KatrynWiese]

Tuff can contain pumice, but it can't "be" pumice.

[@tranjavanadbia123]

TUFF

[@caskamohamed1510]

Well explanation same times I can say better lecture

[@ansammaphilip6977]

Can you help me to find out the type of stone found in my land. Can you please give me your mail id