Lava is the molten substance released by volcanoes, and is an Italian word meaning ‘flooding’. The Earth’s crust is largely made up of solidified lava. Lava is often used to make jewelry. In fact, lava and gagate jewelry were also fashionable in the 19th century during the so-called Victorian period.
Coral is the skeleton of many small marine organisms that comprise a colony. These organisms are polyps, each a few millimeters in size. When a new polyp is born, it attaches its skeleton to the colony and thus expands it. In coral colonies, along with the polyps, some single-celled algae coexist, which photosynthesize and supply food to the polyps, and at the same time secrete pigments that color the colonies, i.e. the corals. Corals can appear in a wide variety of colors such as pink-red, beige, white, as well as black (Yusuri coral). It is supposed to fend off negativity and enhance sexuality.