Many changes in the revised guides focus on the sections dealing with diamonds. The most controversial issues concern weight measurement and lasering The Federal Trade Commission's revised Guides for the Jewelry Industry have been published in final form; they officially took effect on May 29. The guides now cover 24 pages in a formal booklet. Earlier, the FTC had issued a 114-page document which detailed the reasoning behind some of its decisions. The document also included selected references to comments made to the commission by various people in the industry. Here are highlights from the gemstone and synthetics sections of the revised guides with, where appropriate, reports on some of the commission's internal discussion of the issues involved. Section 23.13. Disclosing existence of artificial coloring, infusing, etc. "If a diamond has been treated by artificial coloring, tin