Question

In crystalloraphy they are mentioning origin and coordinate system......If you take some powder sample how do you define origin and x,y,z axis...?

Answer 1

it is just an imaginary axis what they are defining in crystalography!!!!

Answer 2

if we have imaginary origin and axes how do we define planes as real..my doubt is (100),(010),(001) planes are same....?..these planes looks same if change the position of origin and axes.....

Answer 3

planes are made from atomic symetry.... and it is at nano scale..... even in powder there could be thousand of crystal repitition