That would depend of its situation, shape, fauna, vegetation, climate or other particularities.
It might be a cascade, a lake, a lush rain forest, a particular animal or plant species, an ethnic group, a mountain range.
If I had to name an island with such a cascade, I would call it Cascade or Crystal Cascade Isle.
But this Island has already a name:
https://en.wikipedia.org/wiki/R%C3%A9union