  Let $\mathfrak{g}$ be an affine Lie algebra with index set $I = \{0, 1, 2,
\cdots , n\}$. It is conjectured that for each Dynkin node $k \in I \setminus
\{0\}$ the affine Lie algebra $\mathfrak{g}$ has a positive geometric crystal.
In this paper we construct a positive geometric crystal for the affine Lie
algebra $D_6^{(1)}$ corresponding to the Dynkin spin node $k= 6$.
