Rocks!

I was looking through my rock collection, and I decided it was time I unravel the mystery of these milky white, waxy smooth rocks we (my parents and I) found in the desert back in the later 1950's or early 1960's. The larger rock on the left looks like wax, and both of them have a smooth, bubbly surface. They both can scratch glass (hardness of 7) and appear to me to be made of quartz. (Click on the photos for a closer look. I think three of them will do that. I don't know why one won't)


The biggest surprise comes when I turn them over. The smaller rock on the right has a crystalline cavity suggesting a broken geode. The rock on the left is a mysterious bunch of drips.



Here is a closer look at the crystals. They are very tiny. I love the milky patterns that look like cirrus clouds. The parts that look darker are actually more clear, allowing the brown background to show through.

And now a closer look at the "drips". I am amazed at how something like this could be formed of rock. I am guessing that it must have been molten.

I searched my rock books and the Internet for an answer. Finally I found a forum headed by a geologist. After posting pictures I found out my rocks are Chalcedony or "white agate", which is a form of quartz. I still don't know how such an unusual pattern was formed.