Marble and quartz slabs buying Belgium

I would like to know your prices for the realization of calacata white marble or quartz stair treads
Descriptions:
1st staircase: 18 steps including 4 rotating ones
24cm flat foot
18cm tall
90cm wide

2nd stairs: 16 steps a landing 2m long x 1.48 wide
25cm flat foot
17.7cm tall
90cm wide