Every mineral is an ore, but every ore is not a mineral.

Answer

### Step-by-Step Solution:

1. **Understanding Minerals and Ores**:
- **Minerals** are naturally occurring substances that have a definite chemical composition and crystalline structure. They are the building blocks of rocks.
- **Ores** are types of minerals or combinations of minerals from which metals or other valuable substances can be extracted profitably. Ores often contain impurities.

2. **Analyzing the Statement**:
- The statement "Every mineral is an ore" suggests that all minerals can be considered ores because they can be mined for extraction.
- The second part of the statement, "but every ore is not a mineral," indicates that not all ores qualify as minerals due to the presence of impurities.

3. **Explaining Why Every Mineral is an Ore**:
- Since minerals can be extracted from ores, every mineral can be classified as an ore. For example, if a mineral like quartz is found in a rock, that rock can be considered an ore because it contains a valuable mineral that can be extracted.

4. **Explaining Why Every Ore is Not a Mineral**:
- Ores can contain a significant amount of impurities (like sand, clay, or other earthy materials) that do not qualify as minerals. For instance, a rock that is primarily composed of dirt and contains only trace amounts of a valuable mineral is not classified as a mineral.

5. **Example for Clarity**:
- Consider aluminum extraction: Bauxite is an ore of aluminum because it contains a high concentration of aluminum minerals and can be mined economically. In contrast, clay may contain some aluminum but is not economically viable for extraction, thus it is not considered an ore.

6. **Conclusion**:
- Therefore, the statement "Every mineral is an ore, but every ore is not a mineral" is true. The first part holds because minerals can be extracted from ores, while the second part is valid due to the presence of impurities in ores.