Saturation

The intensity or purity of a colour, running from greyish or brownish at the weak end to vivid at the strong. Of the three dimensions of colour, hue, tone and saturation, this one moves price hardest. Grey and brown masks are the enemies: a stone that shrugs them off in ordinary daylight is showing you saturation. Words like vivid on a report belong to that laboratory's own scale, not a universal one.