Gulf Coast Living Online

CRYSTAL

Multifaceted Beauty

Written by Sam Schunk

The word crystal has been around for quite some time, as it is derived from the Ancient Greek term krustallos, meaning both “ice” and “rock crystal,” that originated from the root word kruos, or “icy cold, frost.” A crystal, also known as a crystalline solid, is defined as “a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions.” While this term has a precise definition in the fields of materials science and solid-state physics, the concept is broader in layman’s terms, as it refers to solid objects with well-defined, appealing geometric shapes.

In nature, the largest concentration of crystals in the earth by volume and weight are those that are part of the Earth’s solid bedrock, which were formed through magmatic and metamorphic processes, resulting in huge masses of crystalline rock. These fascinating materials also form out of precipitation of fluids, most commonly of water, with examples being glaciers, sea ice and snow. Some living organisms even have the ability to make crystals, such as mollusks which can produce calcite and aragonite. Nearly all common metals such as bronze are, in fact, polycrystals.

Crystallization is the process of forming a crystalline structure from a fluid or from materials dissolved in the fluid. The structure of a crystal depends upon multiple variables, including the ambient pressure, the chemistry of the fluid, and the conditions under which it is produced. Under the right circumstances, crystals can grow to substantial sizes, like the single selenite crystals found in Mexico’s Cave of the Crystals that have exceeded 35 feet in length and 13 feet in diameter.

Gemstones display the innate versatility of crystal to superior advantage and numerous gems are made of quartz, the second most abundant mineral in the Earth’s continental crust. Quartzite gems naturally occur in a gorgeous array of hues, ranging from completely transparent to rich ebony.

Some quartz varieties are known simply by their distinctive color, such as milky, rose and smoky. The term milky describes white quartzite stones that vary from translucent to opaque in tone. Rose quartz stones fall squarely in the red range, representing shades from pale pink to rosy red. With hues falling anywhere between brown to gray in the color continuum, smoky quartz gems are noted for their opaque shimmer.

Popular gemstones such as agate, amethysts, aventurine, carnelian, citrine, jasper, onyx, and tiger’s eye are also forms of quartz. Agate naturally occurs in a gamut of colors, such as royal blues, rusty browns, reddish shades, opalescent fire, and even rainbow gems. These stones are characterized by their brightness of color and fineness of grain. Agates are typically associated with volcanic or various metamorphic rocks.

Amethyst is a transparent, coarse-grained variety of quartz, long established as the most significant quartz stone used in jewelry. Although amethysts, by their very definition, are purple, gems may vary in color from pale lilac to deep purple. The lighter shades, often referred to as “Rose de France,” were frequently utilized in Victorian jewelry. Darker colored amethysts are the most valuable, particularly the rich purple with rose flashes, known as the “Siberian” style.

Aventurine is characterized by a trans-lucent glow, plus the presence of stripes or flecks within the rock surface that give these gems a shimmering, glistening shine. Most frequently occurring in shades of green, aventurine may also be blue, brown, gray, orange or yellow.

Ranging from yellow to dark brown, naturally occurring citrine has become more and more of a rarity. Most commercial citrines are, in fact, chemically treated amethysts. Jasper usually occurs in brown, green, red or yellow, although it may also be found in its rarer blue form, and it is noted for having breaks along its surface. Stones with the colors in bands or stripes are called banded or striped jasper.

Onyx occurs in nearly every color, with the notable exceptions being blue and purple. It has colored bands that are usually black or white running parallel along its surface, unlike the less uniform striations within agate. Sardonyx is a variant with banded stripes that are red or sard, referring to a dark red stone that is similar to carnelian. Since olden times, chemicals have been used to highlight the reds and yellows within sardonyx and to produce the rich ebony of the stones known as “black onyx.”

Tiger’s eye generally ranges from golden to reddish brown in hue. These opaque gems are normally cut en cabochon, meaning that they are shaped and polished rather than faceted, which results in a convex top and flat bottom.

Crystal gems come in myriad other forms, including the aquamarine, garnet, hematite, jade, lapis lazuli, malachite, moonstone, peridot and turquoise, among many other stunning examples.

Take a closer look at crystal, and you will see that every color of the rainbow is gloriously represented within these beautiful stones!