Controlled reaction conditions in simple, template-free hydrothermal processes yield pure tetragonal zircon-type I41/amd TmGdV O4 nanocrystals with well-defined specific morphologies and sizes. Nitrate reagents under mild conditions (180∘C, pH=7, autogenous pressure) produce from square, hexagon and lozenge nanocrystals with sides starting in 20nm, to porous spindles, nanotubes, nanorods and nanobelts depending of the reaction times. They exhibit photoluminescence in ∼1.95μm similar to bulk single crystals. For the lowest Tm3+ concentration (0.2 % mol) in GdV O4 measured 3H4 and 3F4 fluorescence lifetimes τ are very near to their radiative values, τrad.