What is the smallest rock you’ve ever seen and did you have to use a microscope ?

Question: What is the smallest rock you've ever seen and did you have to use a microscope ?
- Keywords:
  rock
Asked by time43ear to Jess on 11 Nov 2019.
- Jessica Franklin answered on 11 Nov 2019:
  
  Rocks come in all shapes and sizes! Every rock is made up of different minerals, sometimes we can see these with our eyes but sometimes we need to use a microscope. Geologists cut very thing slices of rock and put them under a microscope to see what they are made of.

Question: What is the smallest rock you've ever seen and did you have to use a microscope ?