Malachite and pyrite

Try dissolving minerals!

Difficulty:
Danger:
Duration:
15 minutes

Reagents

Safety

  • Put on protective gloves and eyewear.
  • Conduct the experiment on the plastic tray.
  • Take protective gloves off before lighting the splint.
General safety rules
  • Do not allow chemicals to come into contact with the eyes or mouth.
  • Keep young children, animals and those not wearing eye protection away from the experimental area.
  • Store this experimental set out of reach of children under 12 years of age.
  • Clean all equipment after use.
  • Make sure that all containers are fully closed and properly stored after use.
  • Ensure that all empty containers are disposed of properly.
  • Do not use any equipment which has not been supplied with the set or recommended in the instructions for use.
  • Do not replace foodstuffs in original container. Dispose of immediately.
General first aid information
  • In case of eye contact: Wash out eye with plenty of water, holding eye open if necessary. Seek immediate medical advice.
  • If swallowed: Wash out mouth with water, drink some fresh water. Do not induce vomiting. Seek immediate medical advice.
  • In case of inhalation: Remove person to fresh air.
  • In case of skin contact and burns: Wash affected area with plenty of water for at least 10 minutes.
  • In case of doubt, seek medical advice without delay. Take the chemical and its container with you.
  • In case of injury always seek medical advice.
Advice for supervising adults
  • The incorrect use of chemicals can cause injury and damage to health. Only carry out those experiments which are listed in the instructions.
  • This experimental set is for use only by children over 12 years.
  • Because children’s abilities vary so much, even within age groups, supervising adults should exercise discretion as to which experiments are suitable and safe for them. The instructions should enable supervisors to assess any experiment to establish its suitability for a particular child.
  • The supervising adult should discuss the warnings and safety information with the child or children before commencing the experiments. Particular attention should be paid to the safe handling of acids, alkalis and flammable liquids.
  • The area surrounding the experiment should be kept clear of any obstructions and away from the storage of food. It should be well lit and ventilated and close to a water supply. A solid table with a heat resistant top should be provided
  • Substances in non-reclosable packaging should be used up (completely) during the course of one experiment, i.e. after opening the package.

FAQ and troubleshooting

How many stones should I put in the beaker?

It doesn't matter – even just one stone will work.

What exactly should I be looking for at the end of the experiment?

Pay attention to the color of the precipitate after adding K{4}_[Fe(CN)6].

I want to repeat the experiment, but I don’t have enough NaHSO4. What should I do?

In this case, use the NaHSO4 that you do have. 4 mL is enough to perform the experiment.

Can I do any experiments with pyrite?

Yes, of course, you can! Perform the malachite experiment, but replace the malachite with pyrite. What color is the reaction mixture at the end of the experiment?

I only have one piece of pyrite. Will it dissolve during the experiment?

No, pyrite won’t dissolve during this particular experiment. It might even glitter more brightly afterwards. Enjoy the results! If you want to keep the pyrite after the experiment, rinse it with water.

I tried the pyrite experiment, but the solution remained transparent.

Just add 10 more drops of the K4[Fe(CN)6] and swirl the beaker gently to mix.

Step-by-step instructions

Some minerals react with acids—how about malachite? NaHSO4 will act as an acid in this experiment.

minerals_malachite-pyrite_en-01

Use some heat from a candle to speed up the reaction.

minerals_malachite-pyrite_en-02

If some metal ions escaped the mineral during the reaction, you will be able to detect them using a reaction with K4[Fe(CN)6].

minerals_malachite-pyrite_en-03

What color do you see where the K4[Fe(CN)6] drops fell?

minerals_malachite-pyrite_en-04

Disposal

Dispose of solid waste along with household garbage. Pour solutions down the sink. Wash with an excess of water.

Scientific description

Malachite

As you probably noticed, malachite is a mineral that contains copper Cu. In fact, malachite consists of (CuOH)2CO3 – basic copper carbonate. This compound has been used as a source of pure copper since antiquity. Nowadays, malachite is most often used as a decorative mineral.

Pyrite

Pyrite has long been known as “fool’s gold”. Indeed, the glittering gold-like appearance of pyrite has deceived many treasure hunters. However, this mineral doesn’t contain any gold Au at all—it’s simply a compound of iron Fe and sulfur S, FeS2.