This is "Standard" size Goshuincho book
 
Measurements : 18 cm (7in)  x 12cm (4 3/4 in), thickness 1.3 cm (a half inch)
Book is accordion-fold binding. Japanese thick WASHI paper used.
 
Covering is plain light grey fabric. Looks  like silk, but might be polyester silky fabric.
This color light grey looks like silvery grey.
Silver is just like "mirror", which is believed as protector (attack back) evils.
 
Thank you for dropping by!
Natsu