Selenite Roses from O’ahu, Hawai’i are some of the few minerals I can actually collect in Hawaii. They are very young, as are our islands.
Selenite roses found in Hawaii are basically crystallized surf and a young mineral as are our islands. Waves hit the (often rugged) coastline and the ocean spray blows on to the land. Sulfate and calcium in the ocean water catch a ride in the ocean spray and as separate chemicals ‘land’ along the coast. Rain washes the chemicals into the ground, where they find each other and crystallize as selenite or gypsum as the surrounding environment dries out, or the (rain) water evaporated. If the conditions are right they can form shapes reminiscent of roses, hence the name, from a few millimeters to many inches is size. Geologically speaking Selenite roses are very young and might be only decades or a few centuries old (this is based on the only scientific source I could find so far). So it is safe to say that as you are reading this, Selenite Roses are still growing in our islands.
Selenite roses are water soluble and should be kept in a dry place. If you put them e.g. in an aquarium they would fall apart and disappear within weeks. Selenite Roses are also delicate fragile and I don’t think they are suitable for e.g. wire wrapping.