This is a Nassarius gemmulata, commonly known as the Jewelled Dogwinkle or Dog Whelk. This specimen is 23mm long, a little less than 1".
Nothing has been done to enhance this shell. It is not painted, dyed, carved or polished. It is 100% natural.
This pic is one of what I hope to be a significant series of macro images of seashells. Click on “view larger” for a better look :o)