Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: skeeter on 18/09/2010 21:16:48

Title: Can someone identify this rock for me?
Post by: skeeter on 18/09/2010 21:16:48

My son is a big rock nut and is always on the hunt for new ones to add to his collection.  My wife found this today out behind the house.  It is a nice light pop bottle green color in outdoor lighting and is about the size of a silver dollar.  Thanks

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.handgundefense.com%2Fpics%2FRock1.jpg&hash=fd9fc60927b33609350c07a564495b98)

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.handgundefense.com%2Fpics%2FRock2.jpg&hash=56af0bb54534cd84d5e1a24e4d78eab9)

Title: Can someone identify this rock for me?
Post by: Bass on 19/09/2010 18:17:52

White looks like quartz- conchoidal fracture is diagnostic.  If you can't scratch it with a pocketknife- then that confirms quartz.  Can't tell about the black material on the outside?

Title: Can someone identify this rock for me?
Post by: Ophiolite on 20/09/2010 09:54:29

The 'coating' ,material looks very much like pink feldspar (probably orthoclase), dark ferromagnesian mineral (probably biotite) and white quartz, which would make the main body - rightly identified as quartz by Bass - part of a quartz vein in a granite.