Mercury (Budh) in the 7th house is a fascinating placement. The 7th house is the house of business, partnerships, and public dealings.
When Mercury sits here, the person becomes a master of trade. But Lal Kitab gives a very specific secret: Their greatest success comes from Iron.
Iron represents Saturn. When Mercury (intellect) befriends Saturn (iron/machinery), the person becomes a "Paras" (Philosopher's Stone). They can take a failing factory, a scrap metal business, or a struggling hardware store and turn it into pure gold. Not only do they become wealthy, but they also "change the pictures" of the lives of everyone who works for them.