Identification – Optional Activity

Identification Experiment – Acid Fizz Test

Introduction

What are you doing?

You’re performing the same chemical test that professional geologists use in the field to quickly identify certain types of rocks and minerals.

What does it show?

This experiment demonstrates how acid reacts with calcium carbonate, creating a distinctive fizzing reaction that helps identify specific mineral families.

Why is this important?

Chemical testing is a fundamental tool in gemology and geology. This simple test can instantly tell you whether a stone contains carbonate minerals, helping you identify limestone, marble, certain pearls, and many other materials. It’s so reliable that geologists carry acid test kits everywhere they work.

Materials Needed

• White vinegar (5% acetic acid)
• Eye dropper or small spoon
• Test materials:
  • White chalk (sidewalk or chalkboard chalk)
  • Clean, dried eggshells
  • Antacid tablets (Tums, Alka-Seltzer)
  • Baking soda
  • Various rocks from yard or local area
  • Seashells (if available)
  • Small pieces of concrete
  • Unknown materials for testing

Safety Requirements

• Adult supervision recommended
• Work in well-ventilated area or outdoors
• Wash hands thoroughly after handling vinegar
• Do not mix vinegar with other chemicals
• Test only on materials you’re allowed to use

Step-by-Step Instructions

Phase 1: Set Up Testing Station (10 minutes)

1. Arrange all test materials

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