world war one - What's this 1917 shell casing, more exactly

I've been gifted this vase that is obviously made out of a large shell casing. It has 'MARZ 1917' stamped on the bottom, plus other less understandable markings: 'St', 'G', '36', 'HL 25'. I'm attac

List of military headstamps - Wikipedia

Large calibre markings (The Western Front Museum)

Artillery shell ww1 hi-res stock photography and images - Alamy

WW1 1917 Western Front Bailleul 6 Pounder Trench Art Shell Case - Sally Antiques

Here's a World War One lighter someone made out of a .303 shell. The cap is a hollowed out bullet. There's the initials RK 1917 faintly tapped into it. : r/lighters

WW1 Trench Art Artillery Shell Vases /b

3-inch gun M1917 Artillery Round base cover my dad found in the basement of our 1957 rancher. : r/mildlyinteresting

564 Ww1 Munitions Stock Photos, High-Res Pictures, and Images - Getty Images

Battle of Passchendaele, Facts, Maps, Summary, & Casualties

world war one - What can I learn from these WW1 shell cases? - History Stack Exchange

World War One Trench Art

Ww1 Shell Casings

1914 1918 Verdun Trench Art Shell From World War I