Question

Salt and quartz are two different examples of clear crystalline solids. How can you tell the difference between salt and quartz?

the size of the crystal

the shape of the crystal

the taste of the crystal

the smell of the crystal

Answer 1

Best: the shape of the crystal. Salt (NaCl) typically forms small cubic crystals; quartz (SiO2) forms hexagonal/prismatic crystals with pointed terminations or irregular conchoidal fracture.

Taste can also distinguish (table salt tastes salty; quartz is not salty), but do NOT taste unknown samples — that can be unsafe. Instead use safe tests:

- Solubility: salt dissolves readily in water; quartz does not.
- Hardness: quartz is hard (Mohs ~7) and will scratch glass; salt is soft (~2) and can be easily scratched.

Size and smell are not reliable ways to tell them apart (both are typically odorless and size varies).