Earth Record
Mineralogy and formation
Not one mineral but several fused together. Eilat stone is a composite of secondary copper minerals: chrysocolla, malachite, turquoise, azurite, and sometimes pseudomalachite, formed in the oxidation zone of copper deposits near Eilat, Israel, at the northern end of the Gulf of Aqaba. King Solomon's mines in the Timna Valley are the traditional source, where copper has been mined for at least 6,000 years.
The blue-green color varies specimen to specimen depending on the relative proportions of chrysocolla (blue), malachite (green), turquoise (blue-green), and azurite (deep blue). No two pieces have exactly the same mineral composition. It is the national stone of Israel. The geology is straightforward: copper weathering in an arid desert climate with enough silica, carbonate, and phosphate to produce multiple secondary minerals in the same deposit.
Chemical FormulaChrysocolla + Malachite + Turquoise + AzuriteCrystal SystemMixedMohs Hardness3.5Specific Gravity2.0-4.0LusterVitreous to waxyColorBlue-green, turquoise, with brown and black patternsIMA StatusrockType LocalityEilat Mountains, Southern District, IsraelIMA NumberNot IMA-approved (mixture, no number) EilatIsrael (Timna Valley)
Telling it apart
Eilat stone is a composite intergrowth of multiple copper minerals, primarily chrysocolla, turquoise, malachite, and azurite, in variable proportions from the Eilat mining district in southern Israel. The identification challenge is that each piece has different dominant minerals, so physical properties vary widely: hardness ranges from 2 to 6 depending on which mineral dominates, and specific gravity ranges from about 2.
0 to 4. 0. There is no single hardness or density value for eilat stone. This variability makes it easy for sellers to label any blue-green composite copper stone as eilat stone regardless of origin. Genuine eilat stone should show multiple distinct copper mineral zones: blue (azurite or chrysocolla), green (malachite), and turquoise-blue (turquoise), intimately mixed in a natural matrix.
Simple chrysocolla from Arizona or Peru is not eilat stone and should not command the locality premium. Under magnification, genuine specimens show intergrown bands and patches of distinctly different minerals rather than a uniform single-mineral mass. The historical mine near Eilat has been intermittently worked for thousands of years, and current supply is limited, which drives premiums for documented material from the original locality.
Spotting the real thing
Color Complexity Genuine eilat stone shows multiple distinct copper mineral colors in a heterogeneous, non-repeating pattern, teal chrysocolla, banded green malachite, sky-blue turquoise, occasional deep blue azurite. The colors blend naturally with irregular boundaries. Dyed or synthetic imitations tend toward uniform color or artificially regular patterning. If the stone is one consistent shade of blue-green without visible mineral variety, it may be dyed chrysocolla or reconstituted material rather than true eilat stone.
Texture Variation True eilat stone has variable texture across its surface because it contains minerals with different hardness and luster. Chrysocolla areas may be waxy or vitreous, malachite zones may be silky, turquoise patches may be porcellanous. Run your thumb across the surface (gently), you should feel subtle texture changes. Uniform texture across the entire surface suggests a single mineral or synthetic material.
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