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<p>[QUOTE=&quot;rlm&#039;s cents, post: 424037, member: 7957&quot;]Only talc and gypsum are softer than gold.&nbsp; So I doubt very seriously that any mineral (rare earth mixture) would not scratch gold.&nbsp; Here is the Moh&#039;s hardness scale.&nbsp; Note the position of a fingernail.&nbsp; That is carotene which is the same material as hair.</p><p><br /></p><p>Hardness&nbsp; &nbsp;&nbsp; Substance or Mineral</p><p>1&nbsp; &nbsp;&nbsp; Talc</p><p>2&nbsp; &nbsp;&nbsp; Gypsum</p><p><b>2.5&nbsp; &nbsp;&nbsp; fingernail</b></p><p><b>2.5 to 3&nbsp; &nbsp;&nbsp; pure gold, silver, aluminium</b></p><p>3&nbsp; &nbsp;&nbsp; Calcite, copper penny</p><p>4&nbsp; &nbsp;&nbsp; Fluorite</p><p>4 to 4.5&nbsp; &nbsp;&nbsp; Platinum</p><p>4 to 5&nbsp; &nbsp;&nbsp; Iron</p><p>5&nbsp; &nbsp;&nbsp; Apatite</p><p>6&nbsp; &nbsp;&nbsp; Orthoclase</p><p>6&nbsp; &nbsp;&nbsp; Titanium</p><p>6.5&nbsp; &nbsp;&nbsp; Iron pyrite</p><p><b>6 to 7&nbsp; &nbsp;&nbsp; Glass, Vitreous pure silica</b></p><p>7&nbsp; &nbsp;&nbsp; Quartz</p><p>7 to 7.5&nbsp; &nbsp;&nbsp; Garnet</p><p>7 to 8&nbsp; &nbsp;&nbsp; Hardened steel</p><p>8&nbsp; &nbsp;&nbsp; Topaz[/QUOTE]</p><p><br /></p>

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