a higher degree of brilliance

?Cutters may take weeks to decide on a strategy for cutting diamonds, and the largest ones can take years to polish. Their internal flaws and fractures often determine not only their eventual weight, but their design as well. In general, it?s up to the diamond whether or not it will eventually be emerald-, brilliant-, or heart-cut. Cutters aren?t just producing a pretty geometric shape; they?re also manipulating it so that light will enter where the cutter wants it to, bounce around inside properly, and emerge from the top, creating brilliance. Also, cutting diamonds isn?t like sawing wood; only diamonds can cut diamonds and it can take hours for a saw to create a fissure in a stone. Diamonds can lose a lot of weight during the process and it?s not unusual for a cutter to grind off up to 50 percent of a diamond?s weight to achieve a higher degree of brilliance.?

?Greg Campbell, Blood Diamonds: Tracing the Deadly Path of the World?s Most Precious Stones, 2002.