Zinc and iron end-member staurolites, as well as three Fe/Zn staurolites with intermediate compositions, have been synthesized in a tetrahedral press at approximately 30 kbar and 750°C. All are dimensionally orthorhombic, but are assumed to be monoclinic by analogy with natural staurolites. Indices of refraction of zinc staurolite are α = 1.683, β = 1.694, γ = 1.700. Lattice parameters for the Fe/Zn series vary linearly with composition, in general consonance with previous models of staurolite crystal chemistry. Disorder of Zn and Fe2+ is tentatively suggested by molar volume data. The effective ionic radius of tetrahedrally-coordinated Zn2+ is 0.57Å (±0.01Å) based on unit cell volumes of synthetic staurolites and on previously published data for Zn2+ tetrahedral oxyanions.