So I've come across this rock/stone of some kind, it really shines when moving it around in the light, noticed it also has some copper like colour vein runing through it.
It weighs 480g, length 11cm. wide 8cm, thickness 2cm
Where it is from, unknown but I got it from my garage I'm from NewZealand so it might be from a tourist spot around the country, just my guess.
Any tips would be great
It is a lump of mica shist, a metamorphic rock, probably formed deep underground in the core of a mountain range as it was being built. Mica schists are very common in orogenic terranes worldwide.
There look to be two types of mica in your specimen: a light one (probably muscovite) and a dark one (probably biotite). It is those micas that provide the reflections. Micas are phyllosilicate minerals - silicates with a parallel-layered structure like wads of leaves (phyllo is Greek for leaf). Each layer can reflect the light, so with a transparent phyllosilicate like muscovite, a wad of them can be very glittery.
There will be other minerals as well, in grains too small to ID from a hand specimen (thin section and microscope needed). Some of those could give rise to iron oxides during weathering, which may explain the brassy patches (which may or may not be your 'copper like colour vein runing through it'.
If you're an information junkie...
[apologies to the general NaturePlus readership for this being off-topic]
You might also be interested to know that the plastic laminate 'Formica' got its name from its early use 'for mica' in electrical components, before the days of the transistor. It is a very good insulator; it was used internally in thermionic valves and elsewhere. (The name has nothing to do with formic acid, as some folks think).
Formica became well known in the 1950s+ for decorative purposes (tabletops, railway carriage linings, etc.). In that form it was produced with patterns printed on paper and interlaminated near the top of the structural layers all impregnated with phenolic or melamine resin as usual and surfaced with Melamine. The big sheets (9x5ft in the USA) then went under heat and pressure to make the finished product.
But before then, it was made differently, using a woven fabric and Bakelite resin. That product had similar electrical properties to mica, but was much easier and cheaper to produce in large quantities than mica.
I know about this because my father, William J. Hardman introduced Formica to the UK. While working for Thomas de la Rue, he was also involved in the development of a prototype carriage for Great Western Railways, which used plastic laminates. He was also a consultant to the BBC, coaching Barry Bucknell on how to DIY with Formica (Barry used to present 'Barry Bucknell's Do It Yourself' in the 1950s). Barry was somewhat renowned for mishaps during his shows, which actually made for more-interesting watching! My Dad, too, would have the odd mishap, usually involving the unceremonious wrapping of the damaged finger with masking tape. I grew up helping Dad with his own DIY, and have a collection of artefacts to do with Formica, including exhibition items. It is in my blood!
Now here's the funny thing...
The Formica brand has had various owners, but it it currently held by Fletcher Building, a company based in your very own New Zealand!
That is fascinating Mike - your father sounds like an extraordinary man, this is such an interesting story.
May I also take this opportunity to thank you for your continued contributions to our forums, your knowledge and interests appear to be boundless. The value that you and others add to these forums is supreme - and it also makes it such a helpful and fun forum to visit.
Thank you, and you're very welcome!
It is a learning experience for me as well, of course. I've have but one pair of eyes; the members of NaturePlus magnify that many-fold. So many unknowns. So many answers from folks with all sorts of backgrounds/experience/insights/opinions - my thanks to them.
The rock a typical example of a common rock type, and it is unlikely that it contains any precious metals/gems (maybe some small garnets; depends on metamorphic grade to some extent).
So isn't really worth anything monetarily. You may place other value on it, however.
Some good interesting information about mica shist thank you Mike.
You can occasionally find specimens on the Holderness coast containing garnets usually water rolled but for once the action the mineral has had to endure in the beach system helps the garnets stand proud of the mica because of the abrasive effect sand and stones have on the softer mica.
I will post a picture as soon as possible.
I know exactly what you're talking about. I have a nice piece of biotite-garnet schist from the river bed at Pass of Killiecrankie, Perthsire, which shows exacly the same thing.
I think those brown crystals are probably oxidized pyrite.
If you scratch one, and it looks metallic, it is (most probably) pyrite; if it looks glassy or sugary, it is probably garnet.
The rock may be lower grade than a schist; it may be a phyllite.
One would need to look at its minerals and textures under a microscope to be sure.
Pyrite occurs in a surprisingly wide range of metamorphic rocks. It is stable across most of the metamorphic grades. It will crystallize and recrystallize as the metamorphic environment (mainly pressure and temperature) varies - during both rising (prograde) and falling (retrograde) metamorphism. Despite being very common, it is a very interesting mineral. Many times I have collected it from the slates of North Wales, but it is always nice to find a new piece, maybe a perfect pyritohedron (pentagonal dodecahedron) or interpenetrating cubes..
Here's a good introduction to this stuff:
'The metamorphism of pyrite and pyritic ores: an overview'
Craig & Vokes
Mineralogical Magazine, Vol.57, 1993, pp.3-18