Zinc markers (also reffered to as white broze) are some of my favorite types of markers. They are very easy to spot because of their blue-gray color.
(Mary Fullerton in Pineville Cemetery located in Pineville, MO)They almost always look new because they are near impervious to weathering. Sadly, these markers were only produced for a short period of time. From the late 1870s to the mid-1930s. These markers were produced by The Monumental Brozne Company of Bridgeport Connecticut and its subsidiaries.