Where to Find Biotite in Utah

Utah has 9 mapped collecting spots that report biotite, spread across 7 counties. The largest share sits in Millard County County with 2 spots. 9 of the spots are on land mapped as publicly accessible.

Spot list checked against source data on April 1, 2026.

Standout biotite spots in Utah

Hand-picked from the full list below, with the reason each one earns a trip.

Marysville
Piute County County
Marysvale earns a top spot for small but well-formed crystals in rhyolite cavities, especially bixbyite, amethyst, and reported rutile or pseudobrookite. UGS describes the occurrence as BLM public land in a mid-Tertiary volcanic field, and Mindat records the same locality north of Marysvale with bixbyite, amethyst, pseudobrookite, and rutile.

Best counties for biotite in Utah

Ranked by the number of mapped biotite spots. County links open the full rockhounding page for that county.

Every biotite spot we track in Utah

Sorted by county. Coordinates open in Google Maps.

Spot	County	Minerals	Coordinates	Access
San Francisco MountainsEly Highway	Beaver County	Diopside Fluorite Galena Garnet Pyrite Scheelite Sphalerite Apatite +7 more	38.4591, -113.3067	Public
Antelope IslandMountain View Trail	Davis County	Garnet Azurite Biotite Chlorite Chrysocolla Epidote Limonite Magnetite +4 more	40.9831, -112.1977	Public
Iron Peak	Iron County	Andesite Augite Biotite Chlorite Magnetite	37.9125, -112.6907	Public
Amasa Valley	Millard County	Albite Biotite Diopside Garnet Gold Idocrase Molybdenite Pyrite +4 more	39.1845, -113.3728	Public
Twin Peak	Millard County	Andesine Apatite Augite Biotite Magnetite	38.7841, -112.7329	Public
Arthur's Fork	Morgan County	Biotite Monazite Molybdenite Uraninite Xenotime	40.9347, -111.7509	Public
MarysvilleWest Bullion Avenue	Piute County	Cinnabar Alunite Albite Biotite Calcite Chlorite Pyrolusite Barite +6 more	38.4494, -112.2304	Public
AltaFlagstaff Mountain Trail	Salt Lake County	Apatite Biotite Barite Cerussite Limonite Rhodochrosite Galena Magnetite +9 more	40.5966, -111.6374	Public
Little CottonwoodLittle Cottonwood Road	Salt Lake County	Apatite Alunite Biotite Hornblende Magnetite Microcline Feldspar Pyrite +5 more	40.5702, -111.7135	Public

Before you go

Read the biotite identification guide so you know what a keeper looks like in the field: Biotite in the encyclopedia.

Biotite in Utah FAQ

Where can you find biotite in Utah?+

The mapped spots concentrate in Millard County County, Salt Lake County County, and Beaver County County. Every spot on this page appears on the map above with coordinates and access notes.

How many biotite spots are mapped in Utah?+

9 spots across 7 counties. The RockHoundR app keeps the same spots on an offline map with public land overlays, geology layers, and your saved finds.

Is it legal to collect biotite in Utah?+

Hand collecting of common rocks and minerals in small amounts for personal use is generally allowed on BLM and U.S. Forest Service land, with limits set by the local field office. National parks, most state parks, and tribal land are closed to collecting. 9 of the 9 mapped spots here sit on land marked public. Always confirm current rules with the managing agency before you dig.

Where else to find biotite

Maine6 spots

More minerals to hunt in Utah

Hunt biotite in Utah with the map in your pocket

RockHoundR puts these spots on an offline map with BLM and Forest Service overlays, geology layers, and a log for your finds.