Rainy days (and Mondays) getting you down? We have the perfect pick-me-up: Theo Fennell’s Secret ­Garden. The 18k gold, tourmaline, diamond, and enamel ring immediately transported us to a sun-soaked, flower-filled estate; coincidentally, that’s how Fennell got the idea for this ingenious jewel (retail: 38,500 GBP). “I was sitting in a great friend of mine’s garden in Bergerac, France, and sketching,” recalls the British designer. “I imagined a secret door leading to a secret garden, and the green of the garden matched the stone, so—voilà!” And while ­Fennell frequently stops to smell the roses, he’s less likely to plant a poppy than to fashion one from gold. “I don’t garden,” he admits. “But I love to watch others doing it!”Magnificent SevenIt took a team of seven (“some of the greatest craftsmen in the world”) about four months to create the Secret Ga