You can use 20 gems to start Chapter 2 early.
Chapter 2:
Place the House of Luck (Purchase in the market for 12,000 coins).
Requires 10 jewels, 30 stone, 20 Iron Ore, and 20 Coal to build.

Visit Lucky Dinner Tables (Purchase in the market for 5,000 coins each). Visit them 12 times (high level). You can collect from them every 5 minutes. Can purchase a maximum of 10. They drop Golden Napkin.

3. Clear 2 Paper Blossom Trees (purchase in the market for 2,000 coins each). These are really pretty!!! 15 whacks each, so takes 30 energy to clear 2.

4. Upgrade the House of Luck to level 2. Requires 15 Golden Napkins (from Lucky Dinner Tables) and 15 Paper Blossoms (from Paper Blossom Trees).