Eilat Stone

Eilat Stone is not one mineral but an intergrown assemblage of secondary copper minerals: malachite, azurite, chrysocolla, turquoise, and occasionally paratacamite. It formed in the oxidation zone of a Precambrian copper sulfide orebody in the Timna Valley, where groundwater and atmospheric oxygen slowly altered primary chalcocite and chalcopyrite into hydrated carbonates, silicates, and phosphates over tens of millions of years.

The distinctive banded blue-green appearance reflects this mixed secondary mineralogy. Bright green bands are malachite (copper carbonate), deeper blue zones are azurite, softer blue-green matrix is chrysocolla (copper silicate), and pale sky-blue nodes may be turquoise where phosphate-rich fluids were present. The proportions vary stone to stone, which is why no two Eilat Stone cabochons look alike.

The Timna Valley itself is one of the oldest continuously worked copper sites on Earth. Egyptian expeditions mined here from roughly 4000 BCE, followed by Edomite and early Israelite operations. The rock-cut shafts, slag heaps, and smelting camps remain visible today. Modern industrial mining began in 1955 and ceased in 1985 when economic copper reserves were exhausted. All Eilat Stone on today's market comes from pre-1985 stockpiles or legacy collector holdings, which is why supply is permanently finite.

Eilat Stone shows characteristic irregular banding and swirling patterns in blue, green, and blue-green, often with dark copper-oxide veins running through the matrix. Hardness varies across a single specimen from roughly 3.5 where malachite dominates to 6 where chrysocolla or turquoise bands are present, averaging around 5. The stone takes a high polish but may show softer patches where azurite weathers.

Compared to single-mineral copper stones, Eilat Stone is more mottled and muted than bright Congo malachite, less uniformly blue than Arizona chrysocolla, and less vivid than Iranian turquoise. A streak test produces pale blue-green powder. Under magnification the intergrowth of different mineral grains is visible at the band boundaries, distinguishing it from dyed or reconstituted imitations that appear homogeneous.