1) Make jokes about diamonds being bad long before there's thought of engagement rings. Get your friends, hopefully her friends, and ideally her to do the same.
2) Make it clear that your objection is not to financial. If you do go with a gem that proves to be less expensive, donate the balance to a cause she believes in. If you do have financial objections, express them separately, in financial terms; don't conflate the issues.
3) Point out that it is not a long-standing tradition, but rather a recently manufactured one.
2) Make it clear that your objection is not to financial. If you do go with a gem that proves to be less expensive, donate the balance to a cause she believes in. If you do have financial objections, express them separately, in financial terms; don't conflate the issues.
3) Point out that it is not a long-standing tradition, but rather a recently manufactured one.
4) Don't skimp on other traditions.