The West Old & New Vol. III Issue I January 2014 | Page 13

area; the major mines are currently inactive. The Yogo dike is a narrow subvertical sheet-like igneous body. It varies from 2 to 26 feet thick and extends for 5 miles (8.0 km), striking at an azimuth of 255°. There has been considerable debate over the years as to the depth of the Yogo dike and how many ounces of rough sapphires per ton it contains. In the late 1970s and early 1980s, Delmer L. Brown, a geological engineer and gemologist, conducted the most thorough scientific exploration up to that time, concluding that the dike was at least 7,000 feet (2,100 m) deep and that the concentration of rough sapphires was not constant throughout the deposit. Brown found that the dike had intruded into a pre-existing fault that had been a conduit for groundwater circulation. Brown showed that the unique characteristics of the Yogo sapphires are related to their geological history. Most sapphires are formed under low pressure and temperature over geologically short periods of time, and this is why most non-Yogo sapphires have imperfections and inconsistent coloring. Yogos show crystalline A brilliant cut purple Yogo sapphire. Only about two The first sapphires found in the United States were discovered on May 5, percent of Yogo sapphires are purple. 1865, along the Missouri River, about 14 miles east of Helena by Ed "Sapphire" Collins. Collins sent the sapphires to Tiffany's in New York City, and to Amsterdam for evaluation; however, those sapphires were of poor coloring and low overall quality, garnering little notice and giving Montana sapphires a poor reputation. Gem Mountain Sapphire Mine is 22 miles west of Philipsburg at the south end of the Sapphire Mountain Range on Skalkaho Pass. The mine as been in business since 1892. They produce sapphire gravel concentrate, Montana Sapphire Gemstones and Jewelry. The business digs up the dirt for you, wash, concentrate it and bring it to the store by the dump truck load. Everything you need to go about finding your own sapphires is at their store. They recommend that you wear your play cloths because they are a hands on kind of place. It will be the Dirtiest, Good, Clean, Family Fun you'll ever have. The store front is located in downtown Philipsburg, Montana. During the summer months you can go out to the mine site and look for your own sapphires in the dirt. It is a wonderful way to be outside and having fun in the sun. Gem Mountain 201 W. Broadway Philipsburg, MT 59858 Phone: (406) 859-GEMS (4367) Toll Free: (866) 459-GEMS (4367) [email protected] The raw gems found in gavel at Gem Mountain Mine. The West Old & New Page 13