  Quantum gases of rare-earth elements are of interest due to the large
magnetic moment of many of those elements, leading to strong dipole-dipole
interactions, as well as an often nonvanishing orbital angular momentum in the
electronic ground state, with prospects for long coherence time Raman
manipulation, and state-dependent lattice potentials. We report on the
realization of a Bose-Einstein condensate of erbium atoms in a
quasielectrostatic optical dipole trap generated by a tightly focused
midinfrared optical beam derived from a $\textrm{CO}_2$ laser near 10.6$\mu$m
in wavelength. The quasistatic dipole trap is loaded from a magneto-optic trap
operating on a narrow-line erbium laser cooling transition near 583nm in
wavelength. Evaporative cooling within the dipole trap takes place in the
presence of a magnetic field gradient to enhance the evaporative speed, and we
produce spin-polarized erbium Bose-Einstein condensates with $3\times10^4$
atoms.
