Articles

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 […]

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 […]