Yes, a snowflake is a mineral.
Let's go through the definition of a mineral to see why a snowflake can be considered a mineral:
- Homogeneous: Snowflakes made of ice water are the same through and through.
- Naturally occurring: Snowflakes can be formed naturally when water freezes in cold air.
- Solid: Ice is solid.
- Inorganic substance: yes.
- Definable chemical composition: H2O
- Orderly arrangement of atoms in a lattice: yes