Mercury (Budh) represents glass, intellect, and the sister. Venus (Shukra) represents beauty, luxury, and the wife.
When these two planets form a negative conjunction or clash ("lada hoga") in a birth chart, it creates a very specific Vastu defect. Dr. Sharma states that you will definitely find a cracked or broken mirror ("toota sheesha") lying somewhere in their house.
This broken mirror is not just bad luck; it is a physical manifestation of the clash between the wife (Venus) and the sister/daughter (Mercury). Keeping it in the house will cause constant arguments between the women of the family and destroy the financial peace of the home.