The garnet-structured compound Ca2NaMg2V3O12 is amenable to growth in the laboratory by synthetic contact metamorphism using a solution Of V2O5 and Na2SiO3 in the approximate ratio 4.3:1 acting on dolomite marble "rock." Cooling a 320 a crucible-charge at -2.6 degrees Cmin(-1) from a soak temperature of 1020 degrees C yielded drusy clusters of crystals exhibiting characteristic {211} and {110} garnet faces, with individual crystals as large as 5mrn. X-ray powder diffraction confirmed a cubic garnet structure with lattice constant= 12.42(7) angstrom. The crystals had a specific gravity of 3.43 gcm(-3), refractive index > 1.8,and Mohs hardness about 4. (c) 2005 Elsevier B.V. All rights reserved.