Re. JP's post of sample cards, and Jamey's "Wild Beads" fig. 8, here is what I have in used beads from the Africa trade. Because of the different shapes, cuts, color variants, and surface luminosities, I had always wondered if these were the same basic bead. The unusual weight and the sample card showing varieties seems to clinch this. Apparently this was quite a popular trade bead in its day, and present scarcity may be due to their use in creating new beads; perhaps the filed-down ones being remnants after material was ground off. Thanks, everyone!