Visit Our Showroom 8000 Locust Mill St. Ellicott City, MD 21043 HanStone Sterling Grey Quartz Countertop HanStone Quartz: This is a sample of Sterling Grey from the HanStone brand of quartz countertops. Han Stone quartz is the new and gorgeous lineup of quartz kitchen countertops offered by the large Korean congolmerate Hanwha.