Hi all
I am a lighting maker and want to have a particular shape of chandelier drop made. I have had quotes from China including the use of K5 and K9 crystal. The manufacturer is primarily a rock crystal worker so, despite there being a fair number of websearch results showing images of items made of these materials looking very much like lead crystal, I am worried that I might end up getting chandelier drops with lots of flaws. I wouldn't personally mind, but this is for a client.
Does anyone have any information on K5 and K9 crystal? Is it glass? I have had no luck on the search engines.