A selection of TEM grids with reference patterns to enable relocating a particular grid area. Theses grids are known as reference, locator, finder or index grids. A number of different patterns have developed with either symbols or alphanumeric coding to quickly find a specific field. The locator or finder grids enable quick and easy checking of a particular feature at a later time or on another TEM. Exact grid square definition is a requirement in forensic and asbestos analysis. Another feature of the reference TEM grids is that when moving around on the grid, earlier found features or particles can be easily relocated. All reference grids are available in copper, some in gold or nickel.