I’m currently working on an early ninth-century Japanese text, which references Yakushi's (Bhaiṣajyaguru) 琉璃 Pure Land. I had for a long time translated 琉璃 as lapis lazuli, but I’ve been cautioned by several people that this is incorrect and instead should be beryl, which apparently (and I’m outside of my linguistic comfort zone here) has etymological roots with vaidūrya. Beryl over lapis lazuli seems to be the standard these days from what I can tell.
But as I’ve read more, it seems that it is more complex than this. Yu Xin’s recent piece shows how it is not at all this straightforward and the term 琉璃 , at least in Chinese, can mean a whole host of things.
Moreover, Raoul Birnbaum’s classic book on Bhaiṣajyaguru makes an extended case that lapis lazuli is appropriate, pointing to features such as its presence in Badakhshan and the descriptions used in Chinese texts and appearing in Chinese artwork.
I've also looked at Shōsōin objects in their online database (https://shosoin.kunaicho.go.jp/search-result?per=30&type=treasures&keyword=瑠璃). But this reveals a whole host of objects currently labeled as ruri, which seem to be mostly or all glass. Interestingly, these include all sorts of colors labeled 黄瑠璃, 藍色瑠璃, 浅緑瑠璃, 緑瑠璃, 白瑠璃 (which is almost clear), and others. The ones that are just plain old 瑠璃 are a deep blue and seem to be glass with the color from cobalt. But it's also not clear to me when those names were given and the names could be late. Documents from the 8th-c. on the treasures seem to mention a 瑠璃念珠 and a 碧瑠璃念珠, but those don't seem to be extant (I believe).
This leads me to two questions:
1) Is there a more recent consensus on how to translate the name of Bhaiṣajyaguru’s Pure Land in canonical sources. Is lapis lazuli preferred to beryl in this case?
2) Do we know how people in early Heian Japan might have understood the term?
My translation will presumably follow the answer to #2, but I’m also curious about #1 (it could make a good footnote at the very least, and I suspect the broader community of scholars could benefit from others' expertise).