Problem with DXF colors

Our company develops a geological software program to visualize and model subsurface data. We’d like to create an export to Sketchfab from our 3D viewer. We’ve found that our 3D DXF doesn’t work as well as we’d like because of the limited color pallet. We modified our DXFs to include real colors, but they are rendered as white in Sketchfab without any color options.

Does anyone know of a fix for the DXF import using real colors? Or, should we consider a different export format?