What is the name of the mineral used to make the pigment 'cobalt blue'? - Quora

How is blue glass made? - Quora

Why is blue pigment so rare in nature? - Quora

What distinguishes a royal blue sapphire from other sapphires? - Quora

Is it right that the red pigment for Ferrari is being manufactured in Gujarat, India? - Quora

What is special about tanzanite? - Quora

What is Carmel Sapphire? - Quora

How is colored glass made? - Quora

Where can you find minerals such as gold, silver, copper and zinc? - Quora

Is blue glass still made with uranium blue? If so, how radioactive is it? - Quora

Is Tanzanite still being mined in the world in 2019? - Quora

What is the difference between raw and cut stone gems? Why do they have different values even though they both contain minerals and are from the same type of rock formation (igneous)?