Lovoa trichilioides (syn. Lovoa klaineana); possibly also contributing is one (or two) other Lovoa spec. of the family Meliaceae, the mahogany family. Not a true (genus Juglans) walnut. Another common name for this, and the international trade name, is dibetou and another is lovoa.
my samples: NOTE: these pics were all taken in very bright incandescent lighting ("soft white" at 2700K) colors will vary under other lighting conditions
both sides of a sample plank of dibetou / Lovoa trichilioides --- HUGE enlargements are present. This sample was loaned to me by Mark Peet whom I thank for this and other contributions to the site.
end grain and end grain closeup of the piece directly above