Neutral
The main chemical component of pebbles is silicon dioxide, which is chemically neutral, neither acidic nor alkaline. This conclusion is based on the following analysis:
Composition determines properties
The main component of pebbles is silicon dioxide (SiO₂), which is a typical silicate mineral with stable chemical properties and does not react with water or weak acids/bases at room temperature. A few pebbles may contain trace amounts of calcium carbonate (CaCO₃), but the proportion is extremely low and does not affect the overall neutral properties.
Authoritative source verification
Baidu Encyclopedia points out that pebbles are mainly composed of silicon dioxide, but does not mention their acidity and alkalinity;
The safety science website clearly states that quartz (the main component is SiO₂) is acid- and alkali-resistant, while pebbles have a lower hardness but similar composition;
Articles related to fish tank landscaping directly mark pebbles as neutral and do not affect the acid-base balance of water quality.
Dispute Exclusion
Although some users speculate that pebbles containing calcium carbonate may be alkaline, authoritative data show that their main component is still silicon dioxide, and the calcium carbonate content is not enough to change the overall properties.
Conclusion: Pebbles are neutral overall and are suitable for environments that are sensitive to acid and alkali (such as fish tank landscaping or architectural decoration).