Earth Science Lab Practical Exam Preparation: Rocks and Minerals

hi everyone today we're practicing for our earth science lab practical exam for this exam you're going to have a page

with directions at another page with the answer booklet station one we're gonna have three stations station one will

have rocks and minerals can you pass me the rocks and minerals please Alicia here you go and then we have a few other

rocks here so the first thing it says for station one is write the code number for the mineral

Below in your answer booklet this is our answer booklet so in the first part we're going to

write this mineral code right here in Min one so I'm going to copy Min one and I'm gonna write down Min one right here

this is important so I know which station you're working at when I'm grading it

number two says examine the mineral sample to determine its luster cleavage fracture streak and hardness check the

box on the table given to you so wait we're going to come to our answer booklet and we're going to look at our

table first we're looking at luster so luster means shine yeah so

for your minerals this is this would be called metallic metallic just looks like a metal

would be non-metallic non-metallic minerals do not look like metals so if I were to look at this

mineral I would say this is metallic for a luster and over here I would check metallic

I'm gonna put it back in my box next we're talking about cleavage or fracture cleavage looks like this it has very

strong edges and they always break evenly almost like squares minerals with no cleavage look like

this it does not have strong edges it does not break in squares same with this these two do not have cleavage instead

we call them fracture so if I were to look at this mineral again

this would be fractured because we don't have any sharp angles we don't have squares it's very uneven so let's go

ahead and check off fracture now we want to look for streak for streak we need something that looks like this this is

called a streak plate what we're going to do is take our mineral and we're just going to scratch it onto our streak

plate if the mineral has a color that comes off on the streak plate we're gonna Mark color in this case we do have

color so we're gonna Mark color if we did not have any color here we would Mark colorless

next we're going to talk about hardness for hardness you're gonna need a glass plate like this never scratch it on your

hand always scratch it on your table now I'm gonna do this on here and I'm just gonna scratch the glass and see if this

mineral scratches the glass in this case it does not it's a little hard to see because we have some old

scratches but this mineral actually did not scratch the glass okay so if it does scratch the glass

then we would um check off heart since this mineral did not scratch the glass I'm gonna check off soft

now the last part we want a flow chart number for this we're going to go back to our directions and I'm just gonna go

through all my whole the whole checklist that I made to find a number a final number for my mineral so in this case

checked off luster is metallic here's metallic I checked off clean a fracture so for metallic I'm gonna go towards

actually we did Harden the soft frequency so my hardness is soft here's soft and then I checked off fracture

here's fracture and finally as per streak I checked off color so we do have a streak

if I go through down this flow chart I see that my number is five and I'm gonna write five for my flowchart

and that's it for the mineral part so this is still station one in station one you're normally going to have one

mineral and two rocks the mineral will be labeled mineral and the rocks will be

labeled rocks make sure you don't confuse them and put them in the wrong places that's very important so notice

we have two rocks and they're labeled Rock A1 and rock B1 we're gonna number four says write the code numbers below

for rock a and rock B in your answer booklet Rock Ace code number is A1 so I'm going to come to my answer

down the code number A1 Rugby's code number is B1 so I'm going to go to my answer booklet and write

down B1 now it's asking for rock a classification and rock a characteristic

so if I read number five it says for both rocks A and B write down whether the rock is classified as an igneous

sedimentary or metamorphic rock right so before we start identifying what type of Rocket is we need to figure out the

characteristics of the Rock right and I'm giving you this for now in your instruction booklet but this is

something that you will have to memorize for the lab practical this will not be available for you in the lab practical

so here I have a sample of a couple rocks to show you how to figure out igneous sedimentary and metamorphic

so for igneous rocks the first thing that you want to look for is interlocking crystals meaning multiple

crystals joined together an example would be this rock right here and do I have another example yeah this

rock right here the shiny little um what would you call it fragments in these rocks are actually crystals if you

see crystals in your rock chances are they're an igneous rock and for characteristics you want to write

interlocking crystals another characteristic you would probably want to look for is glassy glassy as you can

see it says only if the whole thing looks like glass so if your rock looks entirely like glass like this you would

say it's glassy and this would also count as an igneous rock lastly you want to look for gas Pockets

or vesicular rocks this would look something like this so it's probably high in the camera

but this has tiny little holes in it because of a volcanic eruption if you see tiny little holes in your

rock and it feels kind of light it's probably has gas Pockets or it's vesticular and we will

so here are my examples of igneous rocks if you find crystals if you see that the whole Rock looks like glass or if you

see there's gas pockets in the Rock it's probably an igneous rock let me put these away now

how do I find out whether I'm looking at a sediment true rock you either want to look for a classic sedimentary rock

meaning a bunch of rocks clumped together or you want to look for a bioclastic

sedimentary rock meaning it has fossils or shells in it so an example would be this

or this these two would be considered clastic sedimentary rocks because there are a bunch of rocks come together this

would be a small small grained sedimentary rock tiny little and this would be a would be a medium or

coarse grained sedimentary rock a little larger Rock okay come together now to look for a bioclassic sedimentary

rock I want to look for fossils or shells and this would be considered a bioclassic sedimentary rock can you see

the shell prints so if you find you find Shell prints or fossils in your rock it's probably a

sedimentary rock and you would say bioclastic bio means living if you find just a bunch of rocks come together like

this it's probably a classic sedimentary rock okay let's move on to our metamorphic rock

say I have so metamorphic rock the only thing you want to look for is whether it's

foliated or not when I say foliated I mean it has alternating dark or light layers something like this as you can

see this rock has layers of light and dark if you see those layers this chances are it's probably a metamorphic

rock and the characteristic would be foliated foliated means layers so let's look at our Rock samples

Rock samples here Rock A1 looks like it has crystals in it so I

want to go to my characteristics and first if it has crystals it's probably going to be an igneous rock so for rock

a classification I'm going to write igneous it's not for characteristics I'm going

to look down on my chart here remember you're going to have to memorize this I'm just going to write interlocking

crystals because I'm seeing crystals here interlocking

sorry about my handwriting crystals I'm going to do the same thing with rock B rough B would be a metamorphic rock

because it has alternating layers of light and dark so I'm gonna go ahead and write down metamorphic for my

classification and for my characteristic I'm going to look back on this chart and I'm gonna

have to memorize this later I'm just going to write foliated for metamorphic because I see layers of dark I'm

and that's it for our Rock section