A customer recently complained that I described the measurements of a bead incorrectly. If I say a bead is 10mm, does that mean wide on the string (perpendicular to string), or thickness hole to hole (parallel to string)?
Describing a bead that is 10mm means it would be round and have an outer dimension of 10mm when measured hole to hole or perpendicular to the hole. For beads with two dimensional measurements, the order of the measurement is length x width. Fire Mountain always puts in the largest dimension first e.g. 10x6mm indicating the bead is 10mm long and 6mm wide.
For a bead like a briolette or teardrop bead the length is the measurement from the top to the bottom (perpendicular to the string) of the bead and the width is the measurement as viewed following the hole (parallel to the string) but in the widest part of the bead.
Melon shape bead
For beads like melon shapes, the length is the distance from one hole to the other and the width is perpendicular to the hole usually at its widest section.