The drop in question is an Orange Glass Marble. Not had a lot of luck so far even with 200% Drop Boosts in effect. According to the Wiki, it can be found in Daiku Cave on hard, so that's where I'll be running this Thursday from around 1600 GMT, until I find that bad boy I guess. 1600 GMT is 1200 EDT, 1100 CDT, 0900 PDT... you know what? Just Google it, save me having to guess your time zone. But yeah, I'll be hanging around either in Kikaigahara Rest Stop, or else I might be fighting the Nurikabe (Just because it's fun to kick its arse for money) this Thursday (October 15th) with a sign over my head stating that I'll be farming. You don't *have* to run with me, unless you also want Orange Glass Marble. If you want to run other dungeons and still benefit from being in a party, I'm cool with that. As long as we all get what we want, I can't complain.
In case you're wondering, I'm trying to craft a Chiami Magatama. I have everything else I need, now only this fecker eludes me.