Dont know as well why they show up to convert when you dont have enough but yeah.

However, she was originally supposed to congratulate players on winning a Legendary/Set item, and does so as of 2.1. I dont think you can, it has to be 9 of exactly the same. Prior to Patch 2.1, she always referred to items she sells in a taunting manner (for example, calling her merchandise a 'good paperweight, for which you can find a use. The drop rate of shards has been raised as well, for the same number of shards as before players will now walk away with 1/3 more legendary items on average. In patch 2.1.1, this was changed: prices increased dramatically, blood shard costs are 5x as high, but the chance to get a legendary from Kadala is now 10%. Gems soak in ambient magic during the time they spend buried in the deep earth of Sanctuary they provide bonuses to essential attributes and also convey special characteristics, among them great fortune and swifter learning. Originally Kadala was selling items cheaply (5 Shards per armor, 10 per ring, 20 per amulet and 15 per weapon), with 0.5% (1.5% after several patches) chance to get a Legendary or Set item. obtain their special powers, convert crafting materials and gems, and more.

This article contains information that is no longer relevant to gameplay, but is kept here for informational purposes. The Caldeum Nightshade is a crafting material in Diablo III, added in Patch 2. Diablo II: Resurrected Review - Pile Of Old Bones

Convert gems diablo 3