Is it feasible to grow crystals from molten carbon?

(Even the toughest substances known to man, such as tantalum carbide, only last for perhaps 200 C beyond the melting point of carbon.) One workaround (which is used to make industrial diamonds) is to use a saturated solution of carbon in molten metal, which allows diamond crystals to be grown at significantly lower temperatures. read more

Graphite crystals, pure carbon, from Sri Lanka are supposedly a bit larger, but as no intact specimen survives, such claims can't be verified. Calcite, that's calcium-carbonate, crystals with a mass of forty tons were mined in the Harding Mine, Taos County, New Mexico. A sixteen-foot long calcite crystal is known in Iceland. read more