A Method for Sequencing the Crown
by Glenn Klein
This is my usual handling of the cutting of the crown facets. Prior to working on the crown, the pavilion has already been cut and polished. The girdle has also been polished.
I begin the crown by cutting the breaks, then work on the mains, and then cut the star facets. All of these facets are completed with my 1200 diamond charged copper lap.
At this point, I use the 45-degree dop, and cut the table down to where it just meets the upper part of the highest star facet. I carefully check to see that the table is parallel to the girdle. You cannot just rely on the 45-degree dop as being correct. A slight angle change or a bit of cheater left or right is almost always necessary.
The gem could have gotten slightly off parallel, because of the heating of the stone and wax during the transferring process. When I believe the table is truly parallel with the girdle, I polish the table.
With the girdle and the table both polished, I am back using the regular dop. I now touch up the star facets with the 1200 lap, so that they meet the table and the mains all the way around. The rest of the crown facets are already meeting, and ready to polish. The stars are polished first. This cuts just slightly up into the table edge, and makes for a nice sharp facet edge, this way. Next the mains are polished. They will reach a bit into the girdle. Lastly, I polish the break facets.
Working on the breaks last does something for me...it reduces the thickness of the girdle! I am always trying to finish with a thin enough girdle to satisfy the judges. They seem to get upset at girdles which are too thick. How one obtains a 2% or a 3% girdle is beyond my means of measuring. I just get the girdle down to where it is thin...almost too thin! Your gem will get more points in judging if the girdle is too thin, rather than if it is too thick. While diamond cutters retain weight by having thick girdles, we competitors must have thin ones, in order to score.
I find that polishing the facets near the girdle first and the facets near the table last, results in more ragged edges. What I am suggesting is to cut facets from the girdle to the table, but polish facets from the table back down to the girdle. You will find that your meets and the facet edges work out better this way. They will be sharp.