Looking back through my historical research posts, jewelry really started out sustainable. People made jewelry out of abundant stones and bones from the animals killed for food and fur. Seeds and plants were often dried and woven together to create a variety of jewelry accessories as well. I suppose it was not until cultures found resources of precious metals and stones, like gold and diamond, from which the category of jewelry became unsustainable.
Such precious and mined materials were and still are tied with cultural manifestations of wealth, beauty, the gods…etc. Cultures all over the world worshiped and coveted these materials, especially with gold in ancient cultures (with ties with divinity and immortality). People, too, desire jewelry made from environmentally unsustainable materials because of their rarity and fanciful promises of luck, wealth, beauty, health…etc.
Of course what materials indicate greater value differ from culture to culture, as well as personal values and beliefs.