I recently had the fun of being partnered with the wonderful Wulf, in the Use the Good Beads Swap. The emphasis was to use your most treasured craft supplies that you've been hoarding for years, always saying 'I need to wait till I have the most perfect, special use for them!' In talking to Wulf, he mentioned needing a mat for the center of his dining table, so I turned to my stash of silk sari yarn. Sadly, none of the yarns in my stash were working just right for what I wanted to make, so I actually bent the swap rules, by doing a yarn trade with someone on Ravelry. So I did use a precious material that had been hoarded, it just hadn't been hoarded by ME. (Don't worry, I made up for it with a second project, a fiber bowl that will be posted tomorrow. My inner Hermione is still afraid I'll be expelled from life for breaking an arbitrary rule.)
I actually wrote my own pattern for this one. It's crocheted with 1.5 skeins of silk sari yarn from Darn Good Yarn. It's made by recycling worn out clothing (saris), keeping the textiles from ending up in a landfill, and at the same time giving fair wages to women & girls in India and Nepal, allowing them to work from home. It might look tiny, as doilies are usually made with delicate lace weight yarn, but this one is actually a heavier worsted weight, so it actually measures 17" across.