Charlesite is a close relative of ettringite, and this specimen (as the Scott Williams label describes) appears to consist of (white) charlesite crystals with an outer layer of bright yellow ettringite. The crystals measure to one centimeter. You would guess the type locality for charlesite to be somewhere in the Kalahari Manganese Fields, but strangely, it is New Jersey; it wasn't described until 1983. These crystals are nicely isolated on the dark contrasting matrix. Ex Collection of Scott Williams, also with another dealer label (priced $250).