Genesis of Topaz in Rhyolite Domes | Topaz Mountain Case Study

The gemstone mineral topaz forms in a variety of genetic environments. In this project, we explore the rhyolite-topaz deposit type through a case study on the Thomas Range in Juab County, Utah. Applying principles of prospecting, we’ll investigate topaz formation in volcanic vents throughout a lava dome in the Cove of Topaz Mountain. You can expect to learn about western Utah's geologic history, lava dome anatomy, geochemistry, crystallization kinetics, thermoluminescence, colour-change reactions, and how to track productive vents to pockets lined with topaz. Video chapters: 0:00 Introduction 0:30 Project Overview 1:03 Geologic History of the Thomas Range 2:11 Lithologies of Topaz Mountain 4:17 Volcanic Vents 5:24 Route Planning 6:44 Mining Claims 7:53 Day 1: Prospecting (Field) 14:06 Day 2: Prospecting (Field) 20:00 Day 3: Prospecting (Field) 20:25 Vent Identification (Field) 25:33 A Productive Vent (Field) 28:12 Day 4: Vent Hopping (Field) 31:24 How Topaz Forms in Rhyolite 34:09 Structural Controls of Deposits 36:38 Secondary Minerals 37:46 Thermoluminescence 38:54 Photosensitivity Experiment 40:11 Inclusions 41:29 Crystal Morphology 43:01 Tips for Collecting Pitstop on I-70 in Utah for roadcut minerals and fossils Coordinates: 38.93380, -110.35140 (Datum: WGS84) Mineral Resources and References: Mobile app I use for prospecting and mapping mineral deposits: Gaia GPS Affiliate link (10% off subscription): https://alnk.to/eDT98T4 Other great videos at the Cove of Topaz Mountain: Bryan Major:    / @thecrystalcollector   Nico Jackson:   / nicojax   Frank & Kyndall:    / thatcampingcouple   The Rugged Rockhound:    / @theruggedrockhound   Guided prospecting tours in the Thomas Range offered by Topaz Mountain Adventures: https://topazmountainadventures.com/ Geologic Map and Cross-Sections of Tertiary Rocks in the Thomas Range and Northern Drum Mountains, Juab County, Utah Download the map: https://ngmdb.usgs.gov/Prodesc/prodde... The Cove (mineral data): https://www.mindat.org/loc-8742.html The Cove (BLM info): https://www.blm.gov/visit/topaz-mountain Book: Holfert, John., Mroch, Walter. (1996). A Field Guide to Topaz and Associated minerals of the Thomas Range, Utah. Volume I. HM Publishing. Book: Hoover, D. B. (1992). Topaz. Butterworth-Heinemann Gem Books. This project is designed to be a complete guide to topaz formation in a rhyolitic setting. The Cove is but one of many of these settings. With a little research, I have prepared a list of other localities with similar volatile-rich rhyolite that are worth investigating for topaz. United States: -Ruby Mountain, Colorado -Thomas Range (northern areas), Utah -Wah Wah Mountains, Utah -Pine Canyon Caldera, Utah -Black Range, New Mexico -Sierra Blanca, Texas -Del Norte County, California Mexico -Zacatecas and San Luis Potosi Spain -Cerro de San Cristobal, Galicia Russia -Ilmen Mountains, Urals Japan -Tamagawa, Akita Prefecture Australia -Mount Surprise, Queensland