The Carthusian (Cartujano) is a horse of average proportions, with perfectly balanced nervous and hormonal systems, a deeply marked sexual differentiation, a spirited temperament and a noble and mild character; an animal of fair response and reactions, the Carthusian is basically hardy, solid and resistent, admits any type of breaking-in and has a shiny and spirited look, with outstanding elevations and extensions and dapple grey, chestnut and black coats.
The worldwide population of popularly known as "closed" Carthusian horses is around one thousand specimens, including adult horses and mares; therefore, its ratio to the total number of Pure Breed Spanish horses (Pura Raza Española, P.R.E.), around 35.000, is approximately of 3%. Furthermore, the degree of Carthusian influence in the P.R.E. livestock is really high, up to 87%. Thus, farmers have never doubted that the Carthusian horse is the base for the maintenance and improvement of the P. R. E., in which it undoubtedly operates as a universal upgrader, to the point where we can assure that every stock has, in more or less proportion, Carthusian blood in its animals.