"Madrona" (Arbustus menziesii) is a complicated mistress. She can be wonderfully easy to turn with resulting figure and color that are easy on the eye. She can also be hard to deal with, as the "sweetness" of the wood chemistry promotes staining and fungii that leave unattractive blotches if the surface does not dry quickly. I have used black leather dye to "ebonize" pieces that are so compromised. Madrone also has a high shrinkage ratio causing turned pieces to take on an oval shape, or the rims of bowls may curve upward near the center pith, over time. Madrone also contains more water while green, contributing to distortion upon drying.
The complementary bowls, vessels, and goblets in the collection are not duplicates, but similar features have been chosen for emphasis by dying them black or leaving the natural color. I have a number of other madrone pieces available, including nested sets from wonderful burlwood shown in the recent work pages.