Any ideas what this could be?

[shivan]

Whilst out looking at the local geology i came across a big rock which seemed like it was red jasper on the outside. After i broke off a bit to look at i noticed the inside was a blue/grey color and it was freckled with another mineral which at first looked like moss. The rock seems almost like a chalcendony but i am not 100% could it be a moss agate? Does not really look like any i could see. Will try for some closer pics tomorrow. The area has a basalt unconformity with sandstone above and rhyolite flow coming from another side.

 

[silver]

is the white stuff milky quartze ? if so maybe crush it and pan it off to see what the yellow ochre coloured stuff is.

 

[Mackka]

Is that feldspar?
Mackka

 

[shivan]

This has been doing my head in a bit. When we first looked at the inside i thought i may have been part of the rhyolite flow but it is distinctly different in color and the darker mineral freckled through it. Wondering if this could be augite? The rest of the rock looks siliceous but i would not have placed it as quartz, it has a very bluee/grey look to it that is hard to show in the photo, though most of the outside was stained red. I could not see any cleavage for feldspar but again could be wrong.
Will try to take a few more photos and see if i can get a better picture.

 

[RedDirtDigger]

Just some thoughts, diagnostic hardness /streak tests etc would be a good start,but I would go with some form of chalcedony or opalite also. The dendritic like inclusions support this.
If the rock has a slippery soapy feel when you run your finger over it and it is softer then quartz I would look towards serpentine or talc.
RDD

 

[shivan]

Thanks RDD, the rock is harder than a knife though quartz does seem to leave a mark, so i am guessing 6-7 range. Streak is white/light grey.

 

[The Green Wanderer]

Man thats a tough one, it looks like a copper silicate in some of the photos but the black flecks are confusing and im not sure if its the light source reflecting blue/green light on it as some of your other photos look like they were taken in natural light which makes it appear grey/brown almost like feldspar.
Im going to take a guess at a member of the plagioclase feldspar group with hornblende inclusions, possibly a specimen of massive albite which would explain why it was near rhyolite flows.

 

[shivan]

G'day The Green Wanderer, i had been wondering if the blue color could have something to do with copper as it was mined nearby, and a few different pyrites are to be found in the surrounding rock, i found a few small specs in this rock too, very small but could be calcopyrite.
None of the light is natural in the photos but i did try my LED torch as it seemed to show the color up a bit better than the rooms light, which made it seem a lot more white. On the outside weathered surfaces there is mostly browns and red, but of the fresh rock is more the grey with a bluish tinge. If it was a feldspar i would have thought to see better cleavage, some poor cleave is present but i am not sure if that is due to the darker inclusion. The darker mineral seems mostly black and green though some is brown closer to the outer edge,i think you are right with hornblende as oppose to augite as cleavage seems greater than 90 degrees. I actually had them back to front and was not until i looked it up i realized augite had the cleavage closer to 90.

 

[The Green Wanderer]

Hmm, chalcopyrite would explain the reddish brown staining both in the fissures and on the outer layer.
Did you end up finding a definate id on it? Or has it been consigned to the unknown box... :/
It sure has a great pattern to it, would look good as an ornamental stone but I think it may be a little soft for cabbing and polishing. The nice waxy, pearlescent feature might be lost.

 

[shivan]

At the moment the rocks are still sitting on my desk in front of me, will get back to figuring them out again soon. I did find a bit of a write up on the area talking about the quartz being impure and of the chalcedonic variety, bluish to greyish in color.
I may try tumbling a bit or two and see how it comes out, i still know where the rest of the rock is if i need a few more bits