diamond-es.mcpsmd.org/ 4 Marquis Drive Gaithersburg, MD 20878 39.13556 -77.23944 Diamond ES4 Marquis DriveGaithersburg,MD 20878 Phone: 240-740-2120 Fax: 301-840-4506 Attendance Office: 240-740-2121 Health Room: 240-740-2122 Mr. Daniel (Dan) Walder, Principal Staff Directory