Hey Mark! We're not sure about the exact brand, but we recommend looking for marble-look subway tile. The tile in the picture looks like a mix of three kinds of marble: Carrara, Calacatta and Statuario. Here are some of our favorite marble-look subway tiles on Houzz:

[Polished Carrara Marble Subway Mosaic Tile, White, 12"x12"[(https://www.houzz.com/products/12x12-carrara-white-grand-brick-subway-mosaic-tile-polished-chip-size-2x4-prvw-vr~9844250)

[4"x16" Subway Backsplash Tile Ceramic, Glossy White Carrara Bathroom Kitchen[(https://www.houzz.com/products/4x16-subway-backsplash-tile-ceramic-glossy-white-carrara-bathroom-kitchen-prvw-vr~49483375)
[Calacatta Gold Polished Marble Subway Tile, 12"x12"[(https://www.houzz.com/products/calacatta-gold-polished-marble-subway-tile-3x6-tiles-set-of-8-prvw-vr~64815990)