Let's analyze each of the given statements about mechanical weathering to determine their correctness:

1. Statement 1: "More compact and highly consolidated rocks are least affected by freeze-thaw weathering."
   • Freeze-thaw weathering occurs when water enters cracks in rocks, freezes, expands, and eventually causes the rock to break apart. More compact and consolidated rocks, due to their density and fewer cracks or voids, are indeed less susceptible to this type of weathering. Hence, this statement is correct.
2. Statement 2: "Shattering of rocks is more common in hot deserts."
   • This process is known as thermal stress weathering or thermal shock. In hot deserts, there is a significant temperature difference between day and night. This causes the outer layer of rocks to expand during the day and contract at night, resulting in shattering. Therefore, this statement is correct.
3. Statement 3: "Crystalline rocks are often prone to exfoliation."
   • Exfoliation is a form of mechanical weathering where successive layers of rock peel off. It is especially common in crystalline rocks such as granite. When these rocks get heated and cool rapidly, the outer layers may expand and contract causing sheet-like layers to peel off. Thus, this statement is correct.

Since all the statements (1, 2, and 3) provided are correct, the correct answer is 1, 2 and 3.