A simple hourglass with sand, non-animated, PBR texture with Glass shader for Blender.
Total Polygons: 36,112 with three separate objects.
The blend file also contains the base object for the hourglass with modifiers, so you can customise it or build it with higher poly counts for better results.
Note: For the sand texture, you'll need to bake it in Blender. It is prepared; just use your custom values and bake.
Thank you!