Hello guys I will show how create a 3dsmax 3d diamond model tutorial.
I have used following techniques shown below in this 3ds max tutorial.
[1]-Click on the Geo sphere button and create a geo sphere with the following size
Place like me
[2]-Convert the geo sphere into the editable poly now select the vertexes mode
Drag the vertexes like this
[3]-Open the material window and click on the opacity map button now select the (falloff)
In the falloff parameter now select the shadow/light in the falloff palette
[4]-Your material should like this 
[5]-Set the skylight like this with the following parameter
[6]-This is final image