Crisp, white card, cut in a rectangle the size of a matchbook. Debossed in shining green ink, the words "Henry Lamperouge" are printed landscape, symmetrically centered. The handwriting is a flowing cursive, such that the name imprinted seems to be written of one long ribbon of green.
Faintly debossed on the bottommost edge are 7 symbols, although exactly which 7 symbols vary from card to card. At most one symbol of seven may be from The Correspondence. Similarly, at most one other may be Clathermontian. Perhaps also there may be symbols from alchemy, goetia, hieroglyphics, tarot decks, card suits, mahjong, etcetera. At least one has received a card with an apple, and another with a chess piece.
When asked, Mr Lamperouge refuses all questions regarding this eclectic practice, and to date shows almost no discernible pattern as to how he assigns the symbols.
Lastly, inscribed neatly upon the back of the card is a return address, in the same green flowing ink. No embossing shows through from the other side.
Regardless of what one attempts to do with the card, short of drenching it; the ink never smudges or runs, and remains shining as though fresh from the quill. Similarly, short of sanding the card down, the debossing never fades, or wears away. The card is utterly opaque when held to light, thin though it is. Mr Lamperouge has never disclosed the particular shade of green he uses in his ink, but all attempts to replicate it have proven fruitless. Mr Lamperouge’s calling card is flammable, and reportedly has the scent of lavender. Cards disposed of this way are not replaced. Scorching or staining the calling card is also possible, with concerted effort.
Modern chemical analysis has reportedly revealed no anomalous properties in the calling card’s composition. If there exists any specific interaction with irrigo light, no-one has been prudent enough to write it down.