I haven't gotten purples from a Cryptarch rank up in probably a month. And when I did it turned into mats. I would really love for Bungie to give us a means to convert from one class material to another. Since my Warlock was my first character, I have something like 450 Hydronic Essences. I'm still struggling with plasteel plating and sapphire wire. If I could just convert those hundreds of warlock mats, I'd be much happier.