Calcite Crystal on Apophyllite and Quartz

Clear Quartz is one one of the most admired minerals by both geology enthusiasts and those practicing the Metaphysical properties of minerals. Quartz is composed of silica (SiO2), and forms an important part of most igneous rocks. Quartz occurs in crystalline masses, and when conditions permit, it forms hexagonal crystals. Perfect crystals are rare. Industrially, crystal Quartz can be cut in a certain way in order for it to produce an electrical charge. This effect makes Quartz very useful for radio, television, and radar. Colors or inclusions in Quartz are due to the presence of other minerals (particularly iron), combining with Quartz during its formation. Common varieties are rose quartz, amethyst, citrine, rutilated, and tourmalinated quartz.

Calcite is one of the most common minerals which grows in a wide variety of different shapes, colors and translucencies. The mineral itself actually belongs to a calcite group of "related carbonates" that are "isomorphous" with each other. All members of the group crystalize in triangular formations, have perfect rhombohedron cleavages, and in transparent rhombohedrons, display strong double refractions. Aragonite and Calcite are similar in chemical composition (polymorphs) but are structured differently, with Calcite forming triangular crystallization and Aragonite forming orthorhombic crystals (three axes planes, at unequal lengths, and all three axes 90 degrees to one another. Unique Calcite formations are created inside the caves where calcium rich water penetrates the cavern's limestone enclosure and slowly drips and flows on top of itself, allowing for the formation of unique stalactite and other globular formations to be created. In this slow process, other minerals can intermix with each other, adding to the interest and forming unusual specimens, such as the one displayed.

Apophyllite frequently occurs in zeolite minerals in basalt, and is less commonly found in pockets of granite. Green Apophyllite occurs most frequently in India where it is found nestled in Stilbite crystals. Colorless and green material from India is sometimes faceted as a collector's gem.