Jump to content
Nugget Shooter Forums

Is it rue that a meteorite will not leave a streak on unglazed tile?


Recommended Posts

The streak test: I read if you rub a meteorite on the back side (unglazed portion) of ceramic tile that UNLESS the meteorite is severely weathered, it won't leave a streak. If the streak is black or gray..it's probably magnetite and if it's reddish brown.... it's probably hematite. Now my question is this, I also read that the fusion crust on meteorites is a glass that is mostly made up of magnetite or hematite. Now when I rub my fusion crusted rocks on the ceramic tile, at first I get a streak (black), however once the crust is rubbed off, I no longer get a streak anymore. Is that what happens when a meteorite is rubbed on unglazed ceramic or am I way off? Any help would be much appreciated.

Link to comment
Share on other sites

The streak test: I read if you rub a meteorite on the back side (unglazed portion) of ceramic tile that UNLESS the meteorite is severely weathered, it won't leave a streak. If the streak is black or gray..it's probably magnetite and if it's reddish brown.... it's probably hematite. Now my question is this, I also read that the fusion crust on meteorites is a glass that is mostly made up of magnetite or hematite. Now when I rub my fusion crusted rocks on the ceramic tile, at first I get a streak (black), however once the crust is rubbed off, I no longer get a streak anymore. Is that what happens when a meteorite is rubbed on unglazed ceramic or am I way off? Any help would be much appreciated.

Sorry, reverse that "a hematite streak is black or gray and magnetite is reddish brown" I had them reversed above.

Link to comment
Share on other sites

Sorry, reverse that "a hematite streak is black or gray and magnetite is reddish brown" I had them reversed above.

digitrick,

You had it right the first time, magnetite---black or gray streak, hematite---reddish brown streak...

The fusion crust of most meteorites is made up of oxides of iron and will give a false streak on the first couple try's. After weathering on earth for thousands of years, the metal will oxidize and expand, therefore causing the meteorite to crack apart. Once this starts, the meteorite is subjected to freezing and heat, this causes the meteorite to break up into smaller pieces. All surface oxides will give a streak, it is the underlying material that will not streak.....

Jim

Link to comment
Share on other sites

digitrick,

You had it right the first time, magnetite---black or gray streak, hematite---reddish brown streak...

The fusion crust of most meteorites is made up of oxides of iron and will give a false streak on the first couple try's. After weathering on earth for thousands of years, the metal will oxidize and expand, therefore causing the meteorite to crack apart. Once this starts, the meteorite is subjected to freezing and heat, this causes the meteorite to break up into smaller pieces. All surface oxides will give a streak, it is the underlying material that will not streak.....

Jim

That's exactly what happened Jim. First couple of rubs left a streak and then it stopped producing a streak which lead me to the assumption that I just rubbed right through the fusion crust if it was a meteorite or whatever coating it was. So, I am NOT putting a whole heck of allot of stock into streak testing on unglazed tile other than to give me a physical idea of how thick the crust is and how hard. I am assuming, if this test was done on several proven meteorites, there may be some sort of correlation to crust hardness and length of time of weathering or even angle of trajectory for atmosphere entry. If the crust bakes longer, maybe it bakes harder or most likely,thicker, again dependent on what it's made out of and such. There just may be too many variables involved to draw any realistic conclusions. Might leave that one to NASA.

Link to comment
Share on other sites

the streak test is very confusing digitrich...the same thing happened with my rock, i did the streak test to...it was black...but when i got to the 'inside' it wouldnt leave a streak...i dont think one can rely to well on the streak test? Do you?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...