Garudapurana 1.68.19

1.68.19

If a diamond seen anywhere in this world, even if only the size of an atom,
is exceedingly light, endowed with qualities in colour, perfectly symmetrical on its facets,
free from lines, spots, blemishes, crow's-feet, flaws, and the like,
and has sharp edges and corners, it is truly an abode of the gods.