The cap of this mushroom can be from 7 to 21 centimeters wide. As in many other species from the Boletus genus, the cap is convex. The color of the cap can be grey, brown or red, but mostly the cap is colored in different tones of more than one of the mentioned color. The pores are tiny and round, and are a bit elongated towards the stipe. They are yellow colored when young, and green when older. They change color to dark blue when cut. Spore print has a brownish olive color.
In reaction with iron sulphate, dark blue or dark green color is produced. The reaction of flesh with potassium hydroxide produces a pinkish orange color.
Boletus splendidus mostly grows between July and September, although in can sometimes be found before, and even after the mentioned time period.
Edible, but it should be heat processed, and one should not eat too large amounts of this mushroom.
It can eventually be confused with Boletus satanas. It is different from the mentioned species in that it has red parts on the stipe as well, and it doesn't have as bad small as Boletus satanas does (smells like garlic or carrion).