"I don't think that even she would have accepted a carat of lunar regolith as an engagement gift."

She probably won't accept a manufactured artificial diamond either- especially since she is blond blued eyed dingbat who like things "natural":). But she might put a nail through her nose because she thinks that is a good idea.

Most of lunar material won't be jewery and the small percent lunar material which is gem quality wouldn't need to be made into engagement rings. But if you divide the lunar material into scientific interesting stuff and decorative type stuff, then a higher percent may be in the latter category. Or one can divide it into stuff which going to be "consumed/used up in some fashion" and stuff which is going be kept and stored as something considered valuable, e.g. comic books were "designed" to be thrown away, but they were collected and considered to be valuable possession. As a guess comic books were probably mostly considered as something of value and to be kept, because of the craftmanship involved to creating them- though this isn't the common perception even by those who collected them- and orginally were practically marketed as "new junk". And btw, this same kind of craftmanship will probably be a major factor in maintaining the value of diamonds- it's mostly undervalued at the moment and fixation mostly upon the gem quality [In other words the complete opposite of comic books- but the craftmanship is common thread between them].

Where is this going? You can't say that Anne Leftleaner won't "accept a carat of lunar regolith" because the art of making jewery from lunar material at moment does not exist. When you have enough gem quality lunar rocks, then they will be crafted into jewery. And in the beginning when first say 1000 pieces of jewery are made, she probably won't be able to buy them because they won't be marketed and sold at K-mart*.

And you probably will have situation where of the first say 100 craftman involved with making stuff out of lunar material, the best of them could become famous "artists" which means that out of the 1000 first pieces ever made which will consider too expensive by most people, at later time, *some* these pieces will be thought to be bought at bargain prices.

*But she might be able to small amount lunar material at K-mart which is marketed maybe similar to a baseball card- a picture of area it is taken from on the Moon, short bit of information printed about it, and small chunk of lunar material, say for 50 bucks. Or maybe less lunar material and it being 30 bucks, and there could a variety of differnent types- more variety than number baseball players or maybe it's less than 50 different "cards". Or maybe even smaller amount- a grain or two of dust, and you buy them like baseball cards, say in a pack of ten.
"Good parents" could sold on idea of encouraging there children to buy these more practical cards which are "educational" and promote their education instead buying useless baseball cards.