The ring system of Uranus has thirteen distinct rings. In order of increasing distance from the planet they are: 1986U2R/ζ, 6, 5, 4, α, β, η, γ, δ, λ, ε, ν, μ rings. They can be divided into three groups: nine narrow main rings (6, 5, 4, α, β, η, γ, δ, ε), two dusty rings (1986U2R/ζ, λ) and two outer rings (μ, ν). The rings of Uranus consist mainly of macroscopic particles and little dust, although dust is known to be present in 1986U2R/ζ, η, δ, λ, ν and μ rings.