In the suttas, there is a simile given for insight knowledge: “It is just as if there were a gem, a beryl, pure, excellent, well cut into eight facets, clear, bright, unflawed, perfect in every respect, strung on a blue, yellow, red, white or orange cord. A man with good eyesight, taking it in his hand and inspecting it, would describe it as such” (DN 2.86).
