In fairness to Mijostyn, both ruby and sapphire are corundum—crystalline aluminum oxide.

mijostyn,

Do you know the effective mass of the SAT arm?  Just looking at the pictures, I cannot even begin to guess whether it is a high mass arm or not.  Most of the mass around the pivot structure is in the non-moving part of the arm, and in any case, mass near the pivot does not affect effective mass as much as mass well beyond the pivot point.  The arm tube looks massive, but, it is a hollow carbon fiber tube of unknown thickness.  

Unfortunately, the SAT website has gone from reasonably informative to vague, feel-good crap.

Dear @dover  : First I was refering to the Netherlands new field coil unipivot not the Kuzma and in the other side ruby and  sapphire is the same material with same characteristics and only different color.

 

 So " touching " you are.

 

R.

ruby and  sapphire is the same material with same characteristics and only different color.

Sure - if you use Wikipaedia for your knowledge base.

I have seen several moving coil cartridges over the years with cantilevers made from sapphire tube.

I have never seen a cantilever with a ruby tube, only solid ruby.

Perhaps you need to look beyond wikipaedia for your knowledge base.