Print Crystals Reading Comprehension
||edHelper's suggested reading level:
||grades 7 to 8
||Flesch-Kincaid grade level:
||amethyst, troubleshooting, undisturbed, phantom, solution, billion, obsidian, supply, interesting, quartz, spectacular, exhibit, research, dissolve, fact, geometric
||Hope Diamond, Smithsonian Institution, Natural History
Spanish: Los cristales
By Sharon Fabian
1 Salt crystals are cubes. Snowflakes have six sides. A diamond has many sides. Minerals like these that have flat smooth sides are all called crystals. Crystals are made of molecules that are all the same shape, and are arranged in a neat pattern. This pattern gives crystals their beautiful geometric shapes. Some crystals can be cut and polished into sparkling jewelry. These crystals are called gemstones. Diamonds, emeralds, amethyst, and rubies are crystals. Some gemstones have colorful names that match the gem. There are green phantom quartz, rainbow obsidian, and Oregon jelly opal.
2 Gemstones form in the Earth over a long period of time. It took about a billion years to form the Hope Diamond, which you can now see in the Smithsonian Institution at the Museum of Natural History.
3 Other crystals form much quicker. In fact, you can grow crystals yourself using just a few everyday ingredients. You can grow crystals from sugar, salt, Epsom salts, or other chemical salts that you can buy at a chemistry supply or drug store.
4 To start, you will need a saturated solution. Mix the Epsom salt, or whatever, in hot water until the water has dissolved all that it can dissolve. This is called a saturated solution.
5 Next, you will need a place where the crystals can grow undisturbed. A glass jar with a large opening at the top will work fine. The crystals will also need something to attach to, so you can put a rock in the jar, or hang a piece of string into the middle of the jar. You can hang the string from a pencil that you lay across the top of the jar. Once your saturated solution has cooled, pour it into the jar, and set the jar someplace where it will not be bumped for a long time.
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