USFG Faceting Dictionary
Jan. 15, 1994, by Fred Van SantRevised Sept. 15, 1999 (Note: For terms dealing with crystal structure, geology, and other such technical subjects, see a textbook.) Adjacent Facets:Two facets on a stone which form a line between them. If facet A shares a line with facet B they are adjacent. Top of Page Alignment: The […]
Cutting by Ear
by Bob Keller, Old Pueblo Lapidary Club I learned to facet on a Facetron in an Old Pueblo Lapidary Club faceting class. I also worked in class on an Imperial outfitted with a dial indicator. The machine that’s been may favorite for several years now is well used Mark I Graves that I acquired cheap. […]
Gemstone Design Conversion Using the Tangent Ratio Method
Background and Primer for the Online Tangent Ratio Converter by Bob Keller, Old Pueblo Lapidary Club A mathematical procedure known as tangent ratio conversion or translation is frequently employed by faceters to optically optimize or tweek a gemstone design’s pavilion and/or crown angles to work with materials of differing refractive indexes (critical angles) and degrees […]
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 […]