Nothing wrong with a blue strand... in that post above I was trying a bit of (Z) fun; after all, a blue pearl is almost as improbable as you-know-which red ones
Can't possibly know if these pearls are drill-able and how: sounds like expertise in catching dragons would be easier to come by then experience drill such unusual pearls.
'Guess we both know that there are lots of rumors (and evidence of cracked pearls!) that non-nacreous pearls are not easy to drill, yet most of them get drilled for use in jewelry. My guess is that they simply are more of a pain and get the folks used to drill 'normal' pearls out of their comfort zone. But, what do I know...