The cap is initially bell-shaped before becoming broadly convex and then flat in maturity (sometimes retaining a broad umbo), and attains a diameter of 2–6 cm (0.8–2.4 in).
The cap surface is slimy (in wet weather) and smooth, and has a lilac or purplish color.
The flesh is white, firm, and thin.
The color fades in maturity, and the cap develops irregular yellowish spots, or becomes yellowish in the center.
Gills are attached to the stem and packed together closely.
They are lilac to violet when young, but become rusty brown to grayish cinnamon when the spores mature.
The stem measures 4–7 cm (1.6–2.8 in) long by 0.5–1.5 cm (0.2–0.6 in) thick, and is nearly equal in width throughout other than a somewhat bulbous base.
It is solid (i.e., not hollow), slimy, smooth, and has violet or purplish colors that are usually lighter than the cap; sometimes, the stem base is more or less white.
The cobweb-like, pale violet partial veil leaves a zone of thin, purple or rusty fibers on the upper stem.
The mushroom has no distinctive taste or odor.
The mushroom is not recommended for consumption.

Cortinarius iodes produces a rusty-brown spore print.
Spores are elliptical, with a finely roughened surface, measuring 8–10 by 5–6.5 μm.
The basidia (spore-bearing cells) are four-spored, club-shaped, and measure 28–39.5 by 9.3–14 μm.
Both cheliocystidia and pleurocystidia are absent from the hymenium; the gill edge is populated by basidia and their undeveloped equivalents, basidioles.
The cap cuticle comprises a distinctive layer of 3–8 μm-wide hyphae that form a layer usually 110–125 μm thick; this layer is less distinct or thinner in old or poorly preserved specimens.
Clamp connections are present in hyphae throughout the fruit body.
The cap is initially bell-shaped before becoming broadly convex and then flat in maturity (sometimes retaining a broad umbo), and attains a diameter of 2–6 cm (0.8–2.4 in). The cap surface is slimy (in wet weather) and smooth, and has a lilac or purplish color. The flesh is white, firm, and thin. The color fades in maturity, and the cap develops irregular yellowish spots, or becomes yellowish in the center. Gills are attached to the stem and packed together closely. They are lilac to violet when young, but become rusty brown to grayish cinnamon when the spores mature. The stem measures 4–7 cm (1.6–2.8 in) long by 0.5–1.5 cm (0.2–0.6 in) thick, and is nearly equal in width throughout other than a somewhat bulbous base. It is solid (i.e., not hollow), slimy, smooth, and has violet or purplish colors that are usually lighter than the cap; sometimes, the stem base is more or less white. The cobweb-like, pale violet partial veil leaves a zone of thin, purple or rusty fibers on the upper stem. The mushroom has no distinctive taste or odor. The mushroom is not recommended for consumption.
Cortinarius iodes produces a rusty-brown spore print. Spores are elliptical, with a finely roughened surface, measuring 8–10 by 5–6.5 μm. The basidia (spore-bearing cells) are four-spored, club-shaped, and measure 28–39.5 by 9.3–14 μm. Both cheliocystidia and pleurocystidia are absent from the hymenium; the gill edge is populated by basidia and their undeveloped equivalents, basidioles. The cap cuticle comprises a distinctive layer of 3–8 μm-wide hyphae that form a layer usually 110–125 μm thick; this layer is less distinct or thinner in old or poorly preserved specimens. Clamp connections are present in hyphae throughout the fruit body.
Cortinarius iodes