... Crystals are all around us. We live on a planet made of minerals; a world of crystals. The rocks that form the universe, the other planets in our solar system and our own planet are made of minerals and minerals are made of crystals. Minerals occur naturally in crystal structures and are composed of various elements. The most common elements on Earth are silicon, oxygen, and half a dozen metallic elements. ... Have your every wondered why gemstones have to be a certain hardness to be worn as jewelry? The particles of dust you see in the air, on tables, and on the floor, most of that is silicon-quartz, which are 7 to 7.5 on the Mohs scale of harness. This dust removes the finish on your dad's car and the polish off your mother's table. Dust is so hard that it actually cuts glass.
... Crystal particles make up our mountains and form the ocean floor. When you walk across the playground sand, you are walking on crystals. Did you ever wonder where the black sand comes from? Try to pick it up with a magnet. It will stick to the magnet because it is a mineral, a metal, and probably iron.
... The earth is formed of three layers: the crust, the mantle, and the core. These are made mostly of solid rock forming minerals. Ever wonder where Rubies and Diamonds are formed. The scientist suspect that diamonds and rubies are both formed in the region 125 miles below the surface in an area called the diamond stratification range. It is believed they are formed in gas bubbles in molten lava. Whenever I see movies with erupting lava such as the Kilauea volcano, Hawaii, I always think about diamonds and rubies shooting to the sky. Actually, this is one of the most common ways for minerals to come to the surface. Some rocks such as pure marble, quartzite, and diamonds are made up of just one mineral, but most are made of two or more minerals.
... It is thought the inner core of the earth is made up of similar in composition to an iron meteorite. Most buildings are made of crystals. Both natural rock and artificial materials are mostly crystalline, even the strength of cement depends on the growth of crystals. Rocks, pebbles, sand, and dust are all formed from eroded crystals. Want to know something funny? Like the rock they come from, these particles stay in the same crystal form even as they get smaller and smaller, even as they become dust in the air.
... How about a cow? Gallstones sometimes form inside your favorite farm animal. Gallstones from a cow have the same crystalline composition as struvite, a natural occurring mineral.
... Ever wonder why a pearl gleans in the sunlight? You know a pearl comes from an oyster don't you. Well when a small piece of sand gets caught in the oyster's insides, and believe me they practically live in the sand their whole life so this can happen often. The oyster has to protect itself from infection. It does this by secreting a fluid, like when you skin your knee and you get a scab, only this stuff is rich in a mineral called aragonite, these tiny crystals form a layer to protect the oyster from infection, just like your mom puts a band-aid on your knee. The tough mineral grows layer upon layer for years on end until it produces a pearl. This layering of aragonite gives the pearl the shine everyone loves.
... How about your own bones? Bones contain a mineral apatite, not appetite like when you're hungry.
... Well-formed crystals are objects of great beauty and extremely rare. Conditions have to be right for them to grow and later change into the minerals and gemstones that we admire and collect. We can talk more about crystals and minerals in our next article.
... Good luck in your rock hounding and your studies of minerals and our earth.