Check out lab grown diamonds. Ethically way better than dirt diamonds, and the price is like 1/5 as well. They also don't have the (solely in my opinion) chintzy sparkle of moissanite.

Shout out to Friendly Diamonds for a recent purchase. My spouse knocked the center stone out of her wedding ring. Ordered a much larger, much (much much much) higher quality in terms of cut color and clarity, and WAY cheaper lab diamond from them.

Look for antique diamonds using older cuts, they're much less sparkly than the modern "brilliant" diamond cut. Plus being antique you're just supporting the antique jewelry business, the cartel already took their cut.

In my humble opinion, sapphires are a great choice, and they also come in a range of beautiful colors. We went with a pinkish-orangish one.