Granite rock with crystals embedded

Prospecting Australia

Help Support Prospecting Australia:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Dec 12, 2016
Messages
1
Reaction score
1
1481540627_img_0385.jpg


Hope this post loads the pic ok.

Found in a creek that has a rep for sapphires, so I'm hoping that's what it is.
Seems to have mica or fools gold in places as well
 
No sapphires in that mate sorry to say. There are sapphire deposits in hard rock in NSW but they are quite rare. It's extremely rare to find sapphire in it's host rock in Australia, most have been weathered out of the rocks and have been redistributed into the drainage channels such as creeks and rivers.
 
Yeah I'd agree with Heatho's comment, no Sapphires unfortunetly.
What you have there looks to be Granite. The dark patches are quartz, lighter off-cream crystals are Feldspar and Mica is a key constituent in most if not all Granite. ;)
 
Welcome to the forum Barracloughm.

Hi, you have a lump of pegmatite, an area in the cooling granite where left over mineral juices formed minerals.
Looks identical to pegmatite I get at oberon with feldspar & smokey/amethyst quartz in it.
If you are near the area where your rock came from again, keep an eye out for lumps of quartz weathering out on slopes...these can lead you to vugh's/cavities in the granite that may contain big crystals.
cheers RDD
 
I was almost thinking Pegmatite RDD, thanks for confirming that it most likely is. I haven't seen enough of them to verify chunks of them.
 
I would go along with pegmatite also.
This is usually in a dyke form ie. a fairly narrow upthrust of composite of granites and other minerals through a fault or ground fissure.

In our locality these dykes run nnw/sse and often kilometres long.
The interesting thing about pegmatite is that it can be the host for beryl which in its best form would be gem emerald.

Some years ago we chased a pegmatite dyke over 2km. looking for the pocket of emerald we were sure to find.
The dyke was around 40cm. thick, we excavated down over 3m. in some places (weathered granite either side) for around 250 carats
of clear beryl crystals but unfortunately too light to be gem quality.

You just may be a lucky one, if you see any deep green colour go easy.
The crystals are a pencil shaped hexagon with flat/slightly bevelled terminations, often in a cluster.
mike
 

Latest posts

Top