MICROCLINE (var. ADULARIA, MOONSTONE)

HISTORY, NAME, LOCALITIES: The adularia or moonstone variety of orthoclase has been known since antiquity.  It is named for its diagnostic, blue-white sheen that is known as adularescence.  Adularia or moonstone is collected in Myanmar, Canada, Switzerland, Madagascar, Brazil, Australia, Tanzania, India, and the United States (California, Virginia, Colorado).

MINERALOGY, PROPERTIES, OCCURRENCE: The adularia or moonstone variety of the feldspar mineral microcline [potassium aluminum silicate, KAlSi₃O₈] crystallizes in the triclinic system as compact masses of tiny, layered crystals.  It is translucent to opaque and varies widely in color, but is distinguished by a diagnostic adularescence, a silvery-white to soft-blue, moon-like sheen that results from the diffusion of reflected of light.  It has a Mohs hardness of 6.0-6.5, an uneven-to-conchoidal fracture, and a specific gravity of 2.54-2.70.  Adularia or moonstone occurs as compact masses within silica-rich igneous rocks.

METAPHYSICAL PROPERTIES, LORE, USES:  Adularia or moonstone has served as a gemstone for more than 3,000 years.  It is cut and polished into cabochon forms to display the attractive adularescence that makes it a popular gemstone.  It is worn as pendants and in rings, earrings, and bracelets.  According to metaphysical practitioners, adularia or moonstone forms a tangible connection with the magic of the moon, provides protection for travelers, creates a path to wisdom, instills hope, and offers access to the natural rhythms of life.

COLLECTORS’ INFORMATION: The adularia or moonstone variety of microcline is collected for its attractive adularescence and its value as a gemstone.

QUARTZ (var. ROCK CRYSTAL)

HISTORY, NAME, LOCALITIES: Rock crystal, which is common and occurs worldwide, has been collected since prehistory.  Notable collecting localities are found in India, Brazil, Germany, Peru, Bolivia, Namibia, Russia, and the United States (Arkansas, Colorado, Maine, Connecticut, Virginia).

MINERALOGY, PROPERTIES, OCCURRENCE: Rock crystal is the transparent, colorless variety of macrocrystalline quartz [silicon dioxide, SiO₂).  The word “quartz” is believed to have originated with the Slavic kwardy, meaning “hard,” in allusion to its substantial hardness.  It crystallizes in the hexagonal system and occurs mainly in hydrothermal veins, granite pegmatites, and as geode linings as short-to-long, horizontally striated, hexagonal, prismatic crystals with pyramidal terminations and distinctive, water-clear transparency.  It has a Mohs hardness of 7.0, a conchoidal fracture, vitreous luster, and specific gravity of 2.65.

METAPHYSICAL PROPERTIES, LORE, USES: Rock crystal has since antiquity been one of the most widely collected of all minerals.  It has served as a gemstone and ornamental stone in many cultures.  Until quartz was synthesized in the 1960s, rock crystal was vital to electronic frequency controls, filters, and timing devices. Modern metaphysical practitioners call rock crystal the “universal crystal” because of its numerous abilities to sharpen insight, enhance spiritual development, improve concentration, refine focus, and energize the mind.

COLLECTORS’ INFORMATION: Rock crystal is widely collected for its brilliant transparency, superb hexagonal crystal development, and frequent occurrence on large plates and in geodes to make interesting display pieces.