THE GOLD OF THAT LAND: Biblical Minerals & Rocks  


54. rust


    1.    brősis, Matthew 6:19-20.

    2.    ios, James 5:3.


Iron rust is an amorphous mixture of hydrous iron oxide minerals that are collectively known as limonite. Goethite [a-Fe3+O(OH)] is the most common of these minerals. Limonite is yellow to yellowish-brown to brown. Crystalline goethite is brown to dark brown with a silky to adamantine luster.

Limonite and goethite form by the chemical weathering of iron and iron-bearing minerals at surface conditions in the presence of oxygen and water. The corrosion of metallic iron reverses the refining process to its ore state, while the weathering of minerals such as iron sulfide produces surface deposits known as gossans, which commonly represent commercial ores.

Iron corrodes readily because of its high chemical reactivity and the nature of the reactions that occur on iron surfaces. Impure iron in contact with air, water, and other solids supports reactions in microscopic electrolytic cells all over its surface. These reactions, in effect, dissolve iron and generate a tiny current that flows to surface impurities, oxidizing the dissolved iron. The resulting rust promotes further reactions because it is porous and flakes off, enlarging a reaction site into a pit that spreads as it follows lines of weakness. The corrosion of ferrous metals is such a costly problem that corrosion control has grown into an industry of its own. Ironically, a developing technology for groundwater remediation utilizes barriers of reactive iron filings to break down certain organic chemicals.

Biblical Background:

The red color of iron rust prompted the ancient Egyptians to believe that Set, their god of evil, had iron bones.

The two biblical Greek words for rust are colloquial and inclusive terms for any metal that decay has eaten away and ruined. The fate of a rusting iron tool or weapon, no matter how keen and shiny when new, warns us of the passing worth of earthly goods in comparison with heavenly treasures. Jesus therefore taught his listeners to seek first the kingdom of God and his righteousness (Matthew 6:33). In the same vein, the Apostle Paul urged, “Since, then, you have been raised with Christ, set your hearts on things above, where Christ is seated at the right hand of God. Set your minds on things above, not on earthly things” (Colossians 3:1-2).


        Ralph, Jolyon, 1993-2004. &

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Last updated: 05/13/06.