It's all to do with ... this remarkable rock has layers that tell the story of the working lives and hardships of miners in the 1800s. A flawless blue topaz gemstone - the largest of its kind - will ...

Ever wonder how Earth scientists examine rocks? We cut them up and throw them under a microscope ... and then everything ...

"These minerals are what's left behind when rock has been in flowing water for eons. Over time, the warm water leaches away all the elements except those that are really insoluble, leaving behind ...