1. Nickel mattes, nickel oxide sinters and other intermediate products of nickel metallurgy; unwrought nickel; nickel waste and scrap

2. A laser beam sinters (melts) the gold flour locally in an extremely small point, and any shape may be ‘drawn’ precisely with the laser beam, in three dimensions.

3. Those sinters are formed of opal-A that replaced microbes, opal-A precipitated as cement, accessory minerals (e.g., kaolinite, jarosite, calcite), biological detritus (e.g., leaves, wood, pollen grains), and lithic detritus.