Many naturally occurring solids possess periodic structures that give rise to visible photonic crystal properties, commonly termed structural colors. Some stunning examples are butterfly wings (one-dimensional, 1-D), abalone shells (1D), sea mouse spines (two-dimensional, 2-D), and natural opals(three-dimensional, 3-D). Exploitation of other periodic natural structures is, however, limited by the inherently large size scale and the low dielectric contrast of the materials. Furthermore, these generally more complex geometries are a challenge to model correctly in order to obtain correct band diagrams. Here we report the development of a high-fidelity, cyclic, sizereduction and infiltration scheme and apply it to a sea urchin exoskeleton to successfully fabricate a highdielectric contrast, 3-D photonic crystal exhibiting a stop band in the mid-IR range. The band structure of the exoskeleton is modeled using level set mathematics and agrees well with the experimental reflectivity exhibited by the 3-D bi-continuous tellurium network of the replicated urchin.