Lecture 40 Identification of minerals and rock samples

[thealmightyX]

21:20 for ROCKS... skip past the mineral stuff...

[THEMANIAC111]

i wander if anyone actually watched all of this.

[AsphaltCowboy57]

I thought that minerals with a hardness of 7 or more such as quartz were not to be used on porcelain streak plates as they were harder than the plate. The purpose of the streak plate is breakdown softer minerals into powder form. By scratching Quartz on the plate, he simply cut into the streak plate leaving powder porcelain behind. That also explains why both the clear and black colored quartz come up with a white streak color.

Am I right? I've got a test over this material soon.

[Golgotha357]

@AsphaltCowboy57

You can test anything on a streak plate. If you look at the properties of quartz or any other hard mineral you will see that they all have streak colors listed and they are all white usually. You may know what quartz is by looking at it but when you have a specimen that you cannot tell what it is it's best to do all tests on it and then check for possibilities. When you get into upper level classes it's not as easy to tell what things are by just one or two tests.

[ipodtouchmaster06]

@scrxbandit because he isnt stupid and learned english. Simple as that.

[mkongola]

@scrxbandit actually not because of what you are thinking but it is because this forum is international and in this era we are striving to think outside the box.

[mkongola]

I think it is appropriate to look at this type of professional presentation possitively and appreciate that thre is a great deal of work that this professor has carried out. I suggest you people comment the observation constructively so that if you happen to have similar opportunity of uploading your presentation(s) similar errors should be minimised. I have much respect to this Professor

[metfan89]

@mkongola perhaps but he obviously doesnt know much about what he is talking about. if are trying to say that pyroxene is a felsic mineral then you shouldnt be allowed to teach the subject

[vidalmadjar]

2_2628872

Pumice is lighter in color (felsic), and scoria is darker. Also, pumice is denser (only 90% porosity)

[StoneTitan]

The obvious reason would be he planed to put it on the internet and for as many people as possible to get something out of his leasson

[Sybian1]

This instructional video is rife with incorrect information. Within the first 5-minutes, he calls pyroxene "felsic," which it's not...it's mafic. Somehow pyroxene shows up on his little chart as felsic. He states he has "no olivine sample to show," and then picks up his first rock sample calling it olivine. Next, he decribes the shape of the clear quartz crystal as a result of "concoidal fracturing." The crystal grew that shape, it wasn't fractured to that shape. I had to stop watching.

[dennisfallen]

thanks for the tip off.i'm currently studying geology and this inaccurate stuff could have f*****d me up.

[2628872]

thank you so much. What is the difference between scoria and pumice?

[pebberbrown]

How is it that you were allowed to post a 59 minute video when the You Tube rules only allow 10 minutes? WHATS UP???