Help find manhwa

MC reincarnated as a maid in at the house where twins brother and sister were being tortured by their uncle(I think) they were being used as guinea pigs in magic experiments mc knew she needed to save them before the sister twin died so she escapes from the mansion and end up at another noble's land where she starts working in a gem store and learns she has the ability to discern gems from magic stones but can't use magic herself there she meets ml the noble who owns the territory and he wants her as one of his people because he thinks her ability very useful