Luann
~Heishi are made from flattish pieces of shell, -a lot of work! whereas Puka shell choker necklaces are composed of hundreds of small sea shell discs naturally worn away and often found with a hole already- Peter Francis described picking up bucketfuls on some tropical beaches. They are the flat tops of spiral shells that resemble conus shells but miniature. So when strung they are much less regular in size.
yours all look to be worked Heishi shell discs.
will try to find you a picture...