Artinite (Hydrated Magnesium Carbonate Hydroxide) forms as a crust of acicular to fibrous crystal aggregates, sometimes forming velvety balls, as with this superb specimen that was in the notable collection of James and Dawn Minette. These are California classics, though many collectors are not aware of this unusual carbonate (it looks a lot more like many silicates - certainly not a typical-looking carbonate). A really pretty example, in fine condition.