Use a sample of marble or a picture as reference.
Make plaster of paris look like marble.
The resulting plaster will have a soupy consistency.
In a mixing bowl combine the water with 2 cups 470 ml of white school glue.
Keep in mind you ll want to fill your container up enough to be able to dip the vase inside without the plaster overflowing.
To obtain a natural look for the veins get a dry sponge and gently tap the veins making the color blend with the ones underneath.
Apply a light base color to the wall.
Polished three dimensional faux venetian plaster enhances both the light and dark tones of the same color creating a sophisticated marble like effect.
Avoid following a pattern when painting the veins.
The plaster should have a similar consistency to thick pancake batter.
Or you can use it neat.
To make plaster of paris with glue instead of flour heat 1 cup 240 ml of water to 100 f 38 c.
Use this plaster within 15 minutes and let it set 3 days to completely dry.
How to create a faux venetian plaster look.
And if you can get acrylic liquid polymer you can use clear shoe polish and you can polish the things you make and they will look amazing.
And if you can buy plaster pigments that would be another good thing for you.
Use a small paintbrush to add veins which should be thin and random.