Not everyone is encountering the same lessons so it is not possible to say any one stone or set of stones will protect you from Mercury Retrograde. That being said, I like to suggest Black Tourmaline for removing negative energy & transforming negative energy into positive energy, plus grounding, which is important for many during this time. However, it is important to remember not everyone sees this as a dreaded time. Think of it like Report Card time: some fear it; some fear what will come as a result of its arrival. But ultimately its arrival and passing means you are now the furthest from it as you move forward, sooooo GET TO WORK!
I would also suggest some clear Quartz to accompany the Black Tourmaline if one is having an especially tough Merc Retro, OR another stone that enhances the cluster that it is with. This enhancing stone should have something to do with the positive transmutation of whatever aspects the individual is have trouble with at this time.
**Hint: Don’t go for BIG money during this time, go for improving your relationship around money.** Cultivation-Cultivation-Cultuvation!
Merc Retro is an opportunity to improve your spiritual environment! That is to say if you want to bring something into your life now is the time to clean up so that everything is nice and in order when it arrives.