Glowing Gemstone With an LED and Instamorph

Introduction: Glowing Gemstone With an LED and Instamorph

About: I am a trustee at Southampton Makerspace, So Make It, and work in freelance Software QA. I have always had an interest in DIY, my first projects involving circuit bending and wearable electronics. My current...

We received some Instamorph at So Make It, our makerspace in Southampton, UK. Here, see how we made a glowing gemstone prop.

We used a coin cell battery and LED; but depending on the voltages and LEDs you use, you may need to include a resistor in your circuit to avoid the LED from blowing.

Step 1: You Will Need...


  • Instamorph
  • An LED
  • A coin cell battery and coin cell holder
  • Solder


  • Bowl for holding hot water
  • Silicone mould in your chosen gemstone shape
  • Heat gun
  • Thermometer
  • Soldering iron

Step 2: Connect Your LED to the Battery

First you need to connect your LED to the battery.

You'll want only a short distance between the LED and the coin cell holder, so first of all cut the wires to the desired length (in our case, about 4cm) and strip the ends bare.

Twist the ends of the wires around the legs of the LEDs, paying attention to their polarity; the long leg of the LED needs to connect to the red wire, the short leg of the LED connects to the black wire.

Make sure the LED turns on and then seal the connection between the LED legs and wires with solder.

Remember to remove the battery before exposing the coin cell holder to heat in the next step.

Step 3: Measure Out and Heat Your Instamorph

Measure out the volume of Instamorph you need by pouring the granules into your silicone mould. Due to its nature, you'll need to make sure the Instamorph granules are heaped into your mould. This gives the impression that you've measured out too much, but this is because once it has cooled again it'll be more compacted into your mould.

Heat the Instamorph following the pack instructions: Pour your Instamorph granules into 60 degree C water and wait until they turn see through.

Step 4: Time to Put It All Together

Pick the Instamorph out of the water using tongs. Be careful in handling it with your bare hands while it is still hot and the hot water runs off.

Push the Instamorph into your silicone mould, making sure to make a hollow where the LED will sit.

Place the LED in the hollow. At this point, you may need to use a heat gun to help warm the Instamorph back up to mould it around the LED and its wires.

Press the coin cell holder into the surface of the Instamorph, and then make the surface of the Instamorph and coin cell holder smooth and flat so that the gemstone will be able to sit flat on a table once turned the right way up.

Make sure not to seal the coin cell holder closed, so that you may put the battery in once the gemstone is cooled. A good way to do this is to make an indent with your finger at the opening.

Step 5: Wait for It to Cool

That's it! All you need to do now is wait for your gemstone to cool. Depending on its size, this may take a while!

Once the gemstone is around skin temperature, you may be able to pop it out of the mould to allow it to cool faster.

Then, pop in the battery, take the gemstone to a dark room and turn it on!

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