Sequencing the Crown
by Fred Van Sant In the most recent issue (82) of FACET TALK is 4-page article by Alexandre Wolkonski for beginners on cutting the round brilliant. After cutting the pavilion he sequences the crown in the order Breaks->Mains->Stars->Table. This article is about a different way to do the crown; it applies to all crowns which […]
Sequencing Facets
by Fred Van Sant (reprinted from the December 1994 issue of the USFG Newsletter with permission from the author and the USFG) In our last newsletter I said that the sequencing of facets is determined by the order in which points on the stone must be made, and that the two most common starting places […]
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 […]
Scratches from the Master Lap
by Dave Woolley, Geologist Senior, VDOTOriginally Published in the Gem and Mineral JournalNewsletter of the Lynchburg Gem and Mineral SocietyDedicated to Bill and Joan Baltzley This column will be devoted to ideas submitted by members who are stone cutters – from tumblers to faceters. If you have a problem or have solved a cutting problem […]
Refractive Index and Critical Angle
by Bob Keller Fundamental Concepts You will often encounter the terms refractive index and critical angle employed in faceting related discussions. Understanding these terms and how they relate to the optical properties of gemstones and different gem materials is fundamental to faceting, designing gemstones, and adapting designs optimized for one material to another. The speed […]
Preforming: What’s The Best Way?
by Fred Van Sant With the new bells and whistles added onto faceting machines in recent years, preforming options have expanded. It used to be that when you cut an octagon shape you always started with the dop arm at 90° and cut 8 facets using a positive stop (Method 1). You cut each one […]
C.A.M. Preform: The Cone
by Fred Van Sant Instead of making the temporary culet point with the CAM facets, some cutters prefer to make rolled cone culet point first, then cut the CAM facets to It. They feel this assures them of starting out with a point that is centered on the dop arm axis. To make the culet […]
Best Index Numbers for Ovals
by Fred Van Sant How does one arrive at the best set of girdle index numbers when improvising or designing an oval with a faceted girdle? The most eye-pleasing shape is that which is as close as we can get to the perfect ellipse, but without a special computer program the index numbers to get […]
Be a Performer, Not a Preformer
by Glenn Klein What is all of this talk about preforming a piece of rough gem material? Why would you preform using a grinder? These and other suggestions are often made in descriptions on how to proceed to facet a gemstone. I see no benefit from preforming. I do see how a lot of good […]
Thoughts on Polishing With Diamond
by Fred Van Sant Most faceters I have talked to agree that the action of diamond in polishing is best when it is a scraping action rather than a tumbling and chipping action. On coarse diamond cutting laps, where the diamond is bonded into the lap surface, you have a scratching or a scraping action. […]