= Solution
A \b[faceted, approximately equiaxed crystal] is indicated. A <truncated octahedron> bounded by low-energy $\{111\}$ and $\{100\}$ facets is a plausible three-dimensional shape for an fcc metal particle; the hexagonal section alone does not uniquely distinguish it from other faceted polyhedra.
The <Wulff construction> minimizes $\sum_i\gamma_iA_i$ at fixed particle volume. Place a plane with normal $\hat{\mathbf n}_i$ a distance $h_i=C\gamma_i$ from a common centre and take the inner envelope. Low-surface-energy orientations survive as large facets. Annealing permits <diffusion> toward this equilibrium morphology, provided the time is sufficient. For a supported or strained <alloy>, substrate adhesion and <elastic energy> modify this simple free-particle construction.
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