Crystals

Crystals are one of the most common forms found in the mineral world. Any solid form of matter, be they ions, molecules or atoms which become uniformly organized into a regularly repeating pattern in three dimensions, can be categorized as a crystal. So, everything from salt and sugar cubes, to even ice, constitutes a form of crystal. Metals, in general, also conform to a crystalline structure.

For the individual who is drawn to the world of natural history, mineralogy and gemology, however, this term takes on a very special and somewhat different meaning. Everything from quartz and ruby, to garnet and diamond, is the realm which fascinates lovers of crystals.

Classically, when one thinks of crystals, the quartz family often comes to mind first. The basic chemical composition of quartz consists of tetrahedra of silicon dioxide (SiO2). In its purest form, quartz is completely transparent (save for fractures and terminations). Quartz crystals are prized for fine termination, clarity and symmetry. Geodes are one fine example of quartz crystals grown undisturbed over millions of years within isolated pockets.

Beyond the colorless form of quartz are the colored variations, such as amethyst, citrine, carnelian, rose quartz and smoky quartz. These are formed when various stray elements are introduced when the crystals are slowly forming. Chalcedony, jasper and onyx are fine examples of this mineral when it is in a microcrystalline matrix infused with various impurities.

Another family of crystals which has captured the imagination of humans for eons is beryl. Considered to be of “precious” quality, this mineral Be3Al2(SiO3)6, is a form of beryllium aluminium cyclosilicate and is often found in crystalline form.

Corundum is another family of crystals which is formed from aluminum oxide (Al2O3). The two most famous forms of this crystal are the ruby and the sapphire.

The queen of all crystals must be given, however, to the diamond. Although it is no different in composition to common carbon graphite, given enough heat and pressure, either naturally or artificially, the octahedral form of diamond can be created.

It is fascinating to note that natural diamonds are only the third hardest substance! Aggregated diamond nanorods and ultrahard fullerites are beyond a 10 on the Mohs hardness scale!

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