Quote Originally Posted by JOB15 View Post
Yeh sure but I don't do grease,, I wanna live long time .

Who makes these colors up. They are grey or blue to my eyes.
Thuringians exist between yellow-green-blue in all possible color variations. In total more than hundred layers have been mined in the old thuringian quarries. All these layers have been classified by most companies in 4 quality levels: yellow green - light green -blue green - (dark) blue.
Some companies simply distinguish green and blue, others listed additional colors like light blue to the above mentioned 4 levels. The most common layer is one that simply looks grey. It was classified as light green quality.