Word of the day: Leaverite
Applied to rocks that are deemed unworthy of collection. As in, "Leave 'er right where you found 'er."
Usage: "Throw it back, that's just a piece of leaverite"
Leaverite is a stone often collected in copious quantities by inexperienced rockhounds, who have not yet seen what really good material looks like. Its has an infinite variety of forms, but it is almost always dull in color, crumbly or fractured, or just plain ugly.
Frequently, it is possible to accidentally collect the prettier specimens of leaverite, simply because all the other rocks in the area were even uglier, rendering it pretty by comparison. You will realize your mistake when you set it beside the rest of the rocks at home, and its oxide-stained, muddy-looking colors begin mock you.