Let the ham sit at room temperature 30 minutes. Preheat the oven to 325 degrees F. Trim off any skin from the ham if needed. Score the ham through the fat in a diagonal crosshatch pattern without cutting into the meat. Place the ham, flat-side down, on a rack in a roasting pan. Pour 1/4 inch of water into the bottom of the pan. Roast the ham until it reaches an internal temperature of about 130 degrees F, about 2 1/2 hours or 15 minutes per pound.
Meanwhile, toast the coriander seeds in dry skillet until fragrant, about 1 minute. Cool and crack in a mortar and pestle or on a cutting board with a small pan. Combine the peach preserves, lemon juice, ginger and coriander in a small saucepan and bring to a boil over medium-high heat. Reduce the heat to low and simmer gently until thickened, 10 to 15 minutes. Strain into a small bowl.
Remove the ham from the oven when it has reached 130 degrees F internally. Increase the oven temperature to 425 degrees F. Spoon or brush some of the glaze all over the ham. Add water as needed to the bottom of the pan. Return the ham to the oven and roast, basting every 10 minutes with the remaining glaze, until glossy, glazed and well browned, about 45 minutes more.