Ergodicity breaking and aging dynamics in a mixture of colloidal clays, Laponite (L) and Montmorillonite (MMT), were investigated. The intensity of the light scattered off L-MMT dispersions scaled with solid volume fraction (ϕ) as, I ∼ ϕ^α, with α = 1.49, for Laponite α = 0.95, for 2 × 10⁻⁴ < ϕ < 8 × 10⁻³, and it remained invariant above ϕ = 8 × 10⁻³. For MMT, α = 1.38 and no such invariance was noticed. Ergodic to non-ergodic transitions were observed in aged samples with a characteristic ergodicity breaking time, τ_EB ≈ 10² − 10⁵ s. Dynamic structure factor, g₁(q,t) exhibited two-mode relaxation, g₁(q,t) = a exp(−t/τ₁) + (1 − a) exp−(t/τ₂)^β. The stretching parameter, β was found to decrease linearly with aging time, t_w whereas slow mode relaxation time increased as τ₂ ∼ exp (bt_w) and τ₁ remained invariant of t_w. Spatial dependence of τ₁ and τ₂ showed, τ₁,τ₂ ∼ q⁻² in the ergodic phase, considered arising from the diffusive motion. After the ergodicity breaking time (t > τ_EB), the slow mode relaxation was no more diffusive and revealed τ₂ ∼ q⁻¹, indicating dynamic arrest of the platelets in the glass phase. The temporal evolution of the slow mode relaxation time τ₂ in full aging regime i.e. above τ_EB, followed a power law growth. The τ_EB was found to decrease with concentration as τ_EB ∼ exp(−ϕ/ϕ₀). A sharp rise in anisotropy, D_p in the L-MMT glass system occurring precisely at the ergodicity breaking time was observed with the overall aging dependence given by D_p ∼ t^0.46_w. Heterogeneity in these samples was probed from the Cole–Cole plot of rheology data. It is concluded that the aging dynamics was governed by the Laponite platelets with the MMT providing a suitable matrix for appropriate interparticle interactions.