Tuesday, July 17, 2012

Siggy's rock

Information to Siggy about the "ROCK" .
In the first place Siggy I have always been fascinated by rocks, rocks that have a different shape or different color have been something I enjoyed. I liked to walk the grounds where ever I have lived and search for rocks. 
Even when I was your age I was looking at the rocks on our farm where we grew up.
We had a lot of sand rocks and I discovered I could break them up into piles of sand. Some of the rocks were yellow and some were more orange and once in a while I would find a rock that was wine colored. I would spend hours breaking these sand rock until they were partials of sand. Why? I just like to see the different colors of the rocks. We also had flint rocks on the farm and nothing would break a flint rock so my pounding rocks were usually flint rocks . 
The rock I sent you the last time was a petrified rock and it  a very interesting story as to how these rocks were formed. 
The rock that I sent last is a geode and they are found in Arkansas. I bought the rock at a place in Arkansas that had many rocks for sale. Janet and I  went on several trips in the last few years I worked and we never passed up a rock selling place much to Janet discussed. She thought my fascination with rocks was silly.
The rock I sent has been   cut open with a saw. I have one here some where that has never been cut and I have tried to  bust it open with a hammer. I can tell you these rocks are hard and my hammer didn't amount to much  with the rock. It is still unbroken. 
You made do what ever you want with the rock . I gave it to you and it is your to do as you please.
One of the most unusual rock I have ever seen are next to your grandma's house she  lived in before she moved . When I saw those Hugh rocks near your pop's house I was filled with wonder...  I wondered where they came from and I wondered what had brought them to where they were on your pop's land.
If you develop a interest in rocks you will have a life time hobby.
  • information about your kind of rock... actually formed, there are theories among geologists about the processes that take place. There are generally two types of geodes. One geode is made out of lava. The other is made from dolomite, a limestone-like sedimentary rock. Each geode is created through different processes. All geodes, no matter how they are formed, must contain hollow bodies in which crystals can form.

How Geodes Are Formed From Dolomite

  • The formation of geodes from dolomite is much more complicated that those formed out of lava rocks. The theory of how dolomite geodes are formed came from geologist Robert Maliva in 1987. His theory goes that the geode cavity formed from a small, hard spheroid that later dissolved and became a cavity, a process that began over 350 million years ago in the warm, shallow waters that once covered what is now the central United States region. Lime sediments grew in the warm saltwater. When the saltwater interacted with sediments rich in calcite, the calcite metastasized into the minerals dolomite and anhydrite.
    The anhydrite then turned into hard spheroid bodies inside the dolomite. Meanwhile, the dolomite changed from a sediment into a hard rock. Anhydrite will dissolve even in the slightest amounts of acid in water. Thus, after acidic water was introduced, outer areas of the anhydrite broke away and were replaced with quartz, which were in the beginning only small fibers of crystal. The centers of the anhydrite bodies were then dispersed completely. Quartz was fed through the rock from water rich with minerals, forming the crystals that grow inside. Over time, the rocks disintegrated, leaving the dolomite to open the elements and causing it to dissolve. 

2 comments:

Sister--Three said...

I will make sure Siggie reads this. She loves rocks and maybe she got that from you. She also loves feathers. I gave her a peacock feather I had saved from Dad's peacocks...so it must have been about 30 years old.

Sunshine said...

I just read this to Siggie. Her new mission is to find some of these sand rocks.