They’re not actual rock pebbles, but glass ones. I picked a goldenish colour, because it gives them a certain coin appearance. It has thirteen letters, like M, C, or B (Market, Communication, Banquet), each with a small set of meanings, like money, trade, and profit in the case of M. It also has three symbols, all of them footprints, for key actions: two from a goat, one ahead of the other, expressing movement; two from a dog, side by side, expressing a stationary or guarding situation; and one from a cockerel to signify new cycles and beginnings. This is still experimental, so I may, in time, add new pebbles. I’ll also be taking notes on a small book to keep track of the readings and be aware of any nuances the oracle might have, like less obvious meanings for a particular letter or how many pebbles to draw.
Yesterday, I used it for the first time and it was an uplifting reading. I made offerings to Mercury at His public altar in Belém and then placed the bag with the pebbles on the altar. I took three at random and got G, M, and L. The first is Cattle (Portuguese Gado), which stands for sexuality, fertility, or prosperity, while M you already know. L means Home (Portuguese Lar) and signifies one’s house, property, but also a place of refuge. Taken together, it simply means a good life: prosperous, sexually and financially satisfying, and a placed called home. A good omen on the first Wednesday of the month.