Although all rockhounds agree that leaverite is the most plentiful rock in the known universe, most pros also know that "you have a very special leaverite there" is a classic play on words.
The term leaverite actually derives from the phrase "leave 'er right there."
It is an in-joke among rock-lookers worldwide used to identify a rock you actually pick up in the field (and maybe wet down) because it looks interesting but turns out to be nothing worth the trouble.
For us, regular leaverite is the stuff that never makes it out of the area where we found it. Well-traveled leaverite, on the other hand, includes the rocks we thought might be worthy of display or of cutting, polishing and wrapping or setting into our jewelry pieces.
Because our workshop is in Hawaii where there are no native rocks just basalt lava, every stone we wrap or set needs to be shipped in. After cleaning up the "finds" we decide to take home, we ship them to Hawaii via USPS flat-rate boxes. Once home, we look again, clean and sometimes break up the stones more than we already have. Often, we find we were, shall we say, "overly optimistic". We really should have "left-'er". This very well-traveled leaverite becomes part of our joke on future geologists.
We have a large and growing rock pile behind our shop. On it is the "well-traveled leaverite" from wherever we have been collecting. It currently includes jaspers from all over the southwest US, some jagged New Mexico fluorites, some Arizona fire-agates, some non-descript, granite-like stones from southern Argentina, pebbles from various other far-flung spots and stones from various locations on the US East Coast.
Children of shop customers sometimes take items from this pile as their own souvenirs. The bulk remains for future geologists to find. We hope they will go slightly nuts trying to figure out where all this stuff came from. They'll know it couldn't possibly have grown where it is. We intend to become a great geological mystery!