White Agate

White agate is a banded chalcedony in white to grayish-white tones. Pure, uncolored chalcedony is naturally white to gray, so white agate represents agate with little iron or other coloring impurity.

It often shows subtle translucent and opaque banding, sometimes with a milky or frosted appearance. White agate is the common, inexpensive base material that is frequently dyed to produce the bright blue, green, pink and purple agate slices sold commercially.

Despite being modest in color, white agate is valued for its clean look, durability and excellent polish, and it pairs well in jewelry with both metals and colored stones.

Agate forms when silica-rich groundwater deposits successive layers of chalcedony inside cavities in volcanic rocks such as basalt. The repeated layering produces the characteristic banding.

White or gray color results simply from the absence of significant coloring impurities; the chalcedony's natural hue ranges from translucent gray to milky white, with whiteness increased by microscopic porosity and fluid inclusions.

White and gray agate is abundant worldwide, particularly in the large Brazilian and Uruguayan basalt agate deposits, which supply much of the rough later dyed into colored agate.

Look for white to gray banding, ranging from translucent to opaque and milky, with a waxy to vitreous luster. Hardness is 6.5-7 (scratches glass), streak white, and thin edges are translucent.

The banded, layered structure distinguishes agate from milky quartz (macrocrystalline, no fine banding) and from white howlite (softer at about 3.5, with gray web-like veins). Common opal is softer (5.5-6.5) and lacks agate's tight banding.

Because white agate is so often a dye substrate, naturally white specimens show subtle, uneven banding rather than the saturated, even color of dyed stones.

White agate is cut into beads, cabochons, slices, coasters and bookends, and its neutral color makes it versatile in jewelry. It is also the principal feedstock for dyed agate products.

Its hardness and toughness suit it for everyday wear, carvings and decorative objects, and polished white agate slices are popular in home decor.

Metaphysically, white agate is associated with clarity, balance, purity and calm; these are traditional spiritual beliefs rather than scientific facts.