Amethyst Geode

The formation of Geodes takes place over millions of years and has many different geological processes.

Hollow Rocks

So, first things first: how do you hollow rock with lots of sparkling crystals inside? Geodes start their lives as a hollow bubble inside a layer of rock. The bubble could be air inside explosive volcanic rock or it could enter into the palm rest of burrows or tree roots.

What About The Crystals?

Geodes that form of air bubbles within volcanic rock are pretty easy to imagine. Think small air bubbles you see in pumice. Now imagine just one of those bubbles completely surrounded by black volcanic rocks and red. As rain pelts on the bubble hot, the chemicals in the rock are slowly released into the water. Some of absorbing water in the hard rock outside of the bubble and was imprisoned for a time inside. As the mineral-rich water through the bubble, tiny crystals are left behind, clinging to the sides of the bubble. Millions of years while this passage in and out flow of water increases gradually crystals in the empty space. The crystal formations might become large single crystals or tight micro-crystals so small that you can not even distinguish one from another.

From a pet home

Let us study the development of our animal burrow bubble ... Long after the animal has changed or the tree died and rotted roots, sediments surrounding the pit are covered by layers and layers of sediment hundreds of feet think. Eventually, the weight of these layers has caused the sediments become rock: sedimentary rock. Just like our volcanic bubble, this bull terrier animal hosts filled mineral water entering and exiting the cavity. And just like the volcanic bubble, a wide variety of crystals are taking shape inside the former home of the animal.

Time flies

Fast forward to modern times. The waterlogged land where our bubbles began has become a vast desert where the howling wind and the sun beats down. The earth, covered with rocks and scrubby brush yields rocks with unusual shapes. Today, you have found a good field of them and have three specimens of nearly all year to break open when you go home.

All geodes are not created equal

The first is quite hollow but for a nice coat of medium-sized blue crystals. The Dugway geodes have bands of blue and pink. The colors come from different minerals that flowed through the bubble so many millions of years. Another specimen is nearly solid all along. The microcrystals have formed wide bands of different colors and the tiny opening in the middle has a thin ring of crystals. Yet another is completely filled with rings of solid brown, red and pink. So, you've really found two geodes and one nodule. Nodule is the name of these round forms when they are filled solid.

Quartz, calcite, or what?

Most geodes have interiors made of quartz or calcite is. Quartz crystals are silicates. Silicates are the most common mineral in the earth's crust. Over 90% of the minerals present in the earth's crust are silicates. That said, you can imagine that silicates are a sizable group with much variation in terms of specific chemical composition.

Calcite is the main ingredient CaCo2 of calcium carbonate dissolved calcium and carbon with some oxygen from the water thrown in.

small changes can make a big difference

Now add in a trace of iron or magnesium or copper, and voila, you have color variation.
traces of magnesium in the form of a layer of calcite dolomite beautiful rose, while the magnesium silicate in the accounts for the purples of amethyst.

Heat can change

Now, if your.