The Scratch Test:
1. Hardness: Calcite is harder than halite.
* Halite: You can easily scratch halite with your fingernail.
* Calcite: Your fingernail will not scratch calcite. You'll need a harder object like a copper penny.
2. Observation:
* Halite: Will likely show cubic crystal shapes (though not always perfect).
* Calcite: May have a variety of crystal shapes, often rhombohedral or with cleavages that create angled surfaces.
Additional Tips:
* Taste: Halite is salty. Be cautious, as some minerals can be harmful if ingested.
* Acid Test: Calcite reacts with weak acid (like vinegar) by fizzing or bubbling. Halite will not react.
Important Note: Always handle minerals with care. Some may be toxic or have sharp edges.
