This listing is for the exact specimens pictured.
WHAT IS IT
Agates are rocks consisting of microcrystalline quartz called chalcedony. They are typically formed in pockets within cooled lava. As water flows though the lava, the pores in the cavities— called vesicles—act as tiny filters which catch silica particles that were in the water. As these particles accumulate, various silica- based minerals can be deposited to create colorful bands in the rock which can be seen whenever the rock is cut open.
• Chalcedony is more soluble than quartz under low-temperature conditions, despite the two minerals being chemically identical. This is thought to be because chalcedony is extremely finely grained (cryptocrystalline), and so has a very high surface area to volume ratio.
• Agate often occurs in geodes and nodules.
• Add this to your geology collection.