Rock salt is a mineral form and is isometric crystals of Sodium Chloride.
It may also contain other elements like magnesium, potassium, manganese, iron, zinc etc.
Mined rock salt is suitable for human consumption.
Rock Salt has digestive stimulant properties, which might be due to its trace minerals.
It promotes digestion and improves appetite.
In ayurveda, Sendha Namak is used with black pepper, ginger, long pepper and cinnamon for improving appetite.