rock with crust, ideas please

[alan p]

Looked at lots of rock and pics but cant find a match for this rock,white part look like it's made of the tiniest white particles held together with a slightly transparent resin and has a sheen to it, the crust is reddish/brown cracked and you can see where the previously fractured sides have a thin covering of the crust, underneath the crust is an orangey/brown toffee looking rock with a grey looking rock underneath the orange part, in the orange and grey part there's the tiniest mix of coloured grains i.e. black pink cream white brown & a bluish/grey, there is also same grains in some areas of the white part which looks like a porridge mix, looks very organic strangely, I guess the outside must have hematite in it but doesn't show on a streak test unless a lot of pressure is applied but then only a faint pink, moves with a magnet but doesn't pick up although I have piece at museum that has lots of bright metal in and clicks to magnet and another piece that has tiny bit of crust with holes like slag, most of what said can only be seen with magnifying glass, there is also a few clear yellowish bits and I don't believe white part is quartz as cant find rock similar,

 

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[Eu_citzen]

The rusty outside is likely limonite.
Can the white be scratched with a knife? Sure looks metamorphic in origin to me.

 

[alan p]

Hi Eu I get what you're saying about limonite so had a look at a lot of images and a read and limonite should have a yellowish streak, so had another streak test on my rock and pressed a lot harder and you really have to look hard to see the slightest faintest of any mark so much I would say no streak really, and cant find an image like my rock, and tried scratching white part and brown part with a very sharp point of blade and no marks on either part of rock, to be honest there's a lot more detail to rock when looking closely with microscope, the piece I have at museum is of same rock but has visible bright metal pieces in it but its been in museum in Cambridge since Jan and hasn't been looked at yet, perhaps it's been binned.

 

[Eu_citzen]

Yes, a yellowish-brown streak.

I think the white is quartz-related. Quartz or Quartzite or similar might fit the bill.
The bright pieces might be mica, which on occasion occurs in quartzite.

As a side note, geologists almost always use a mere 10x magnification for specimens. You might get lost on details otherwise.

 

[DDancer]

I'd call it a jasper. Its not uncommon to see two colors together like that and the hardness as well as the gloss of the specimen suggest that its a jasper.

 

[alan p]

I agree that the orange/brown look like jasper which then should connect it to quartz as I have thought that the white looks a bit chert looking with naked eye, there's actually three colours which includes a grey, all three colours have some tiny grains in parts and 100% no mica its solid metal and connects to magnet with a good click so I have thought that maybe its been mixed in with some ore and got metal from there as one piece also has a slag looking crust attached to it, all three pieces are attracted to a magnet but just one piece sticks and other two just move, the piece with the slag crust appears to have minute bits of metal but I think maybe just eye trickery, ithought with the crust on all pieces and the metal flashes of meteorite came at me then I woke up ha !, still its exiting to look at for me, couple of pics with the slag crust piece

 

[ice9]

Just a rock, not a meteorite, impossible to ID from your photos. Try joining a local rockhound club, or talking to a geologist at a local museum or university.