How to make glow in the dark crystals
These crystals are easy to grow and they are simple to make. They are called Alum crystals. They are the most reliable crystal you can grow and if you add some household ingredients you can make it glow in the dark. The materials you will need in this solution are a fluorescent highlighter pen (You can use any color for a different effect) make sure the highlighter can glow under a black light, usually the color will work but many blue pens don’t glow. You will also need alum sold in a pickling, the final ingredient will be water.
First carefully cut open the highlighters and then remove the ink strip (you may use gloves, since a highlighter can stain your fingers). Now you want to pour half a cup of hot water into a clean container. Then you squeeze the ink strip and let the ink into the water, discard the ink strip when you are done squeezing out the ink. Now you carefully stir in the alum, a little at a time and slowly, until it stops dissolving. The next step is to loosely cover the container with a coffee filter or a paper towel (this step needs to be done to not let dust in) then let it sit overnight and in the morning you should see small alum crystals sitting at the bottom, if there aren’t any then give it more time.
How to make large glow in the dark crystals
You will need to repeat the steps above to do this. First if there are crystals pour the solution into a clean jar. Now collect the small crystals which are called seed crystals. Tie a nylon line around the largest, best shaped crystal and tie the other end to a flat object like a popsicle stick or a ruler. Now you will hang the seed and make sure it is in the liquid and isn’t touching the sides or the bottom. It may take a few times to get the right length. now cover it with the paper towel or coffee filter and let the crystal grow. Grow your crystal until it suits you, if you see small crystals forming on the side of the jar remove your hanging crystal and pour the solution into a clean jar and put the crystal and the paper towel back on the jar, keep repeating until right size.
How to make the crystals glow
When you are done will your crystal take it out of the solution and let it dry when it is dry put it under the black light or the sun (It depends on the color). Now you can display your newly formed crystal, but if it comes in contact will water it will dissolve so dust it with a cloth.
How to make it really glow
If you want your Alum crystal to glow without the black light then mix phosphorescent pigment into the solution and usually the glow will remain. If you want to make it glow on the inside since the alum crystal is clear then mix phosphorescent pigment and clear nail polish into the solution then you can paint over, it will glow on the inside and it will be protected from being damaged by water and humidity preserving it.