Rabastan watched Hermione out of the corner of his eye. Moste Potente Fungai and Darker Purposes was an original...But he had all the important bits he would ever need from it. He set Cursed Potions aside and said, "Well? Any closer? I got as much out of the book as I could think would relate. Two potions almost match what you have written there, but not exactly."
He sighed and reached in his robe pockets, "But, I think perhaps Purist Magicks of Potionary might be our best bet." He withdrew the tiny book and enlarged it. "Have a look see." Purist was the oldest, most careworn book in his collection, and by that mark, probably the darkest of his books.
Rabastan lifted the brittle, yellowed pages and leafed through quickly, "It has a concordance of every potion ever concocted, and it updates near to hourly." He indicated the slightly newer pages at the very back of the book.
"What you do is open to the first page, list all the ingredients out loud and it will start finding similar potions. I'm wondering if you have all of the ingredients though, there are a few potions whose ingredients aren't as easily identified. This book will sort the potions by closest match, so you'll have a wider range to look through."