Switch to full style
This is a place for all questions about Geology (not only related to Petroleum exploration and production). You can also ask our experts to determine rock types from photographs in this forum.
Post a reply

Rock ID Please . . .

Mon Sep 10, 2012 5:49 pm

Hi All . . .

I found this rock in my backyard after having a septic system implemented. The rock was unearthed at approximately 8 feet. It is very heavy, at least 2-3 pounds, and has milky white quartz inside.

In the first picture I'm shining a flashlight into the partially hollow center.

What do you think it is?

Thanks in advance . . .
Attachments
rock10.jpeg
r8.jpg
r7.jpg

Re: Rock ID Please . . .

Wed Sep 12, 2012 1:25 pm

Hello Katie,
What you saw in your compound, as you correctly said contains milky non crystalline Quartz in the hollow centre of the mineral body The whole unit appears to be part of a big Dolerite "dyke" or plug in the Country composed of massive pink Feldspar.
The inner centre originally must have contained some extraneous body which subsequently was dissolved by an invading hot granitic fluid which eventually cooled to deposit the Quartz in a rather "myrmartic" irregular form as Quartz is usually the last of all minerals to crystallise out of granitic rich igneous solutions.
This is my own honest submission.
Regards.
Dipo O. Obileye
The Exploration Learning Centre,
Charter Tech Limited,
Lagos, Nigeria.
Post a reply