This information comes Department of Lands website.
I’m reposting here because data has a way of disppearring off the internet.
(Reference: Information comes from Gemstones of Idaho written by Alice Allebaugh.)

GEMSTONE OR ROCK NAME
COUNTY
LOCATION
AGATES – NODULES
Cryptocrystalline Quartz
CUSTER
• Lime Creek 12 miles south of Challis along US 93A
• Iris along Willow Creek Road off US 93A south of Challis
OWYHEE • Squaw Creek
AGATES – PLUME
Cryptocrystalline Quartz
OWYHEE • Graveyard Point southwest of Homedale (private mine) west of US 95 near Idaho-Oregon border
AGATES – GREEN & GREEN MOSS
Cryptocrystalline Quartz
BLAINE • 9 miles north of Muldoon, south of Cary, along Little Wood River
LEMHI • Parker Mountain near Salmon
AGATES – BANDED & SCENIC
Cryptocrystalline Quartz
LEMHI • South of Meyers Cove
AGATES – LIGHT BLUE
Cryptocrystalline Quartz
GEM • Near Emmett
AGATES – RED
Cryptocrystalline Quartz
CUSTER • 3 miles west of Challis
AGATES – RED & GREEN
Cryptocrystalline Quartz
OWYHEE • Eastern fringe of Succor Creek
AGATIZED WOOD CUSTER • 12 miles south of Challis along US 93A
WASHINGTON • Hog Creek 8-10 miles northwest of Weiser
AMETHYST BLAINE • Pole Creek
CUSTER • Lost River
OWYHEE • War Eagle Mountain near Silver City
• “Indian Bathtub” area
VALLEY • Paddy Flat and Big Creek area near Cascade
ANALCITE
isometric zeolite mineral; last zeolite to be deposited.
BLAINE • Golden Bell Mine in head of gulch containing Minnie Moore Mine near Bellevue
CUSTER • South of Challis
APATITE
Calcium phosphate
CUSTER • Blackbird Mining District
AQUAMARINE ELMORE • Above Atlanta
AZURITE
Copper carbonate
ADAMS • Seven Devils Mining District
CUSTER • Alder Creek and Bayhorse Mining Districts
LATAH • Hoodoo Mining District
SHOSHONE • Little North Fork area near Kellogg and Mullan
OWYHEE • South Mountain area
BERYL – GREEN LATAH • In pegmatites of the Levi Anderson, Muscovite and other mica mines near Avon
BERYL – DARK BLUE ELMORE • In primitive area near Atlanta
CALCITE – FLUORESCENT
Calcium carbonate
CUSTER • Alder Creek, Bayhorse and Yankee Fork Mining Districts
CALCITE – RHOMBOHEDRONS
Calcium Carbonate
ADAMS • White Mountain Mine, Seven Devils Mining District
BLAINE • Hailey (Mineral Hill) Mining District
CALCITE – MASSIVE / GRANULAR
Calcium Carbonate
SHOSHONE • Sunshine, Bunker Hill, Hypotheek, Hecla, Standard-Mammoth and Hercules Mines, Coeur d’Alene Mining District
CASSITERITE
Tin Oxide
LEMHI • Silver Creek
• Panther Creek near junction of Moyer Creek, Cobalt area
OWYHEE • Along Jordan Creek near Silver City
CEYLONITE
Spinel
BLAINE • Wild Horse Canyon east side of Hyndman Peak
ADAMS • Rocky Flat area near New Meadows and Seven Devils Mining District
CHABAZITE
Form of Zeolite
ADAMS • Blue Jacket Mine, Seven Devils Mining District
BOISE • Warm Springs Creek area east of Boise
ELMORE • 5 miles below Glenns Ferry
CHALCEDONY – FLUORESCENT TWIN FALLS • Rabbit Springs on Idaho-Nevada border US 93
CHALCEDONY – VARIETIES CUSTER • Willow Creek Road south of Challis off US 93A
• Mahogany Creek in Pahsimeroi Valley and near North Fork of Lost River
OWYHEE • War Eagle and Florida Mountain areas near Silver City
BLAINE • Pole Creek Summit near Galena and south of Carey along Little Wood River
LATAH • Potato Hill
LEMHI • Parker Mountain Mining District
VALLEY • Yellow Pine Mining District
CHRYSOCOLLA BENEWAH • Alder Creek
ADAMS • Arkansas Mine, et al., Seven Devils Mining District
LATAH • Hoodoo Mining District
SHOSHONE • Coeur d’Alene Mining District
CINNABAR CUSTER • Alder Creek Mining District
VALLEY • Yellow Pine Mining District
WASHINGTON • Near Weiser
CRYSTALS – COBALT LEMHI • Blackbird Mining District
OWYHEE • Silver City area
CRYSTALS – QUARTZ CUSTER • Near Bayhorse and in Yankee Fork Mining District
BENEWAH • Crystal Peak northeast of Fernwood
IDAHO • McKinley Gulch in Slate Creek and Ruby Meadows
OWYHEE • Long Gulch south of Silver City
VALLEY • Northwest of Donnelly
CORUNDUM OWYHEE • Near Silver City
CLEARWATER • Along Rhodes and Orofino Creeks near Pierce
VALLEY • Along Gold Fork Creek northeast of Donnelly
ADAMS • Rock Flat gold placers near New Meadows
IDAHO • Near (Resort) Burgdorf
DIAMONDS ADAMS • Little Goose Creek area near New Meadows
DOGTOOTH SPAR
Calcite Crystals
IDAHO • Adjacent to US 95 midway between Riggins and Lucile
EPIDOTE ADAMS • Peacock, Queen, Copper Boy and other mines, Seven Devils Mining District
CLEARWATER • Pierce area
CUSTER • Near Park Creek
LEMHI • Mackinaw and Carmen Creek Mining Districts
OWYHEE • Near Silver City
VALLEY • North of Paddy Flat Road northeast of Donnelly
• Deep Creek north of McCall
FELDSPAR – MOONSTONE CAMAS • Near Fairfield
FELDSPAR – PALE YELLOW BOISE • Shafer Creek
FELDSPAR – CLEAR FREMONT • Crystal Butte 18 miles north of St. Anthony
FELDSPAR – VARIETIES LEMHI • Blackbird Mining District
OWYHEE • Silver City area
FLUORITE – PURPLE CUSTER • Empire Mine, Alder Creek Mining District
LEHMI • South of Meyers Cove
VALLEY • Stibnite
FOSSILS – SEE ZOISITE
GARNET – STAR BENEWAH • Purdue Creek, vicinity of Bovill and Clarkia and along East Fork of Emerald Creek (US Forest Service fee)
GARNET – LIME SILICATE ADAMS • Seven Devils Mining District
BEAR LAKE • Lanes Creek (NW 1/4, Section 9, Township 8 S, Range 43 E, BM)
CUSTER • Phi Kappa Canyon near head of Big Lost River
• Copper Basin at head of East Fork of Big Lost River
• Alder Creek Mining District near Mackay
GARNET – ROSE-RED
BROWN-RED
CLEARWATER • Rhodes Creek, Orofino area, near Clearwater River
• Pierce area
NEZ PERCE • Clearwater River near Lewiston
GARNET – RED SHOSHONE • Canyon Creek
• Purdue Creek
GARNET – PURPLE-RED OWYHEE • Silver City area
GARNET – YELLOW-GREEN WASHINGTON • Iron Mountain northeast of Weiser
GARNET – RED-PINK ADAMS • White Monument, Peacock and Copper Key mines near Kinney Point
IDAHO • On main Salmon River 10 miles above Riggins
HEDENBERGITE & ILVAITE OWYHEE • South Mountain Mining District
HEMATITE – PEBBLES BANNOCK • Lane’s Creek gravel bars
BOISE • Boise Basin placers
HEMATITE ADAMS • Rock Flat on Goose Creek
CUSTER • In dumps of copper mines, Alder Creek Mining District
LATAH • Iron Mountain 20 miles north of Moscow
WASHINGTON • Iron Mountain
JADE FREMONT • Bitch Creek north of Tetonia
JASPER – RED WITH GREEN MALACHITE BEAR LAKE • Hummingbird Mine area in Paris Canyon near Montpelier
JASPER – BRUNEAU OWYHEE • 50 road miles south of Bruneau in Bruneau River Canyon
JASPER – VARIETIES BLAINE • South of Carey along Little Wood River
CUSTER • Crane Creek Reservoir area, 12 miles south of Challis along US 93A
• Alder Creek Mining District near Mackay
OWYHEE • West of US 95 south of Homedale near Idaho-Oregon border
WASHINGTON • Signal Light 10 miles northwest of Weiser
• Beacon Hill near Weiser
KYANITE SHOSHONE • Goat Mountain and Blackdome Peak area
MALACHITE ADAMS • Seven Devils Mining District
BEAR LAKE • Hummingbird Mine in Paris Canyon
CUSTER • Alder Creek Mining District
FREMONT • Skull Canyon area two miles east of Kaufman
LATAH • Hoodoo District
SHOSHONE • Coeur d’Alene and adjacent mining districts
MARCASITE LEMHI • 1 mile south of Salmon
OWYHEE • Associated with silver mines near Silver City
SHOSHONE • In the Gold Hunter Mine, Coeur d’Alene Mining District
MORDENITE CUSTER • 15 miles south of Challis
LEMHI • Near Salmon
MYRMEKITE VALLEY • Yellow Pine Mining District
NAUMANNITE CUSTER • Yankee Fork District
LEMHI • Parker Mountain Mines, Gravel Range Mining District
OWYHEE • DeLamar Mine on Florida Mountain near Silver City
OPAL – FIRE CLARK • Spencer Opal Mine near Spencer (private – fee charged)
GEM • Lava beds of Squaw Butte, Emmett area, and Black Canyon Dam
LATAH • 5 miles south of Forney on Opal Creek
OWYHEE • Near Givens Hot Springs, Oreana and on the west side of Squaw Creek
OPAL – BANDED CUSTER • 3 miles west of Challis
OWYHEE • Squaw Creek
OPAL – HYALITE NEZ PERCE • Near Lewiston area
OPAL – COLORED
GEM • Red to salmon-pink to whites and pale blues along Willow Creek near Emmett
OPAL – VARIETIES LEMHI • Pahsimeroi Valley near May
OPAL – COMMON CUSTER • Poison Creek
LATAH • Moscow Opal Mines
LEMHI • Panther Creek
• Pahsimeroi Valley near May
NEZ PERCE • Clearwater River Valley
OWYHEE • 17 miles south of Marsing
• Castle Creek
• Mule Springs
• Givens Hot Springs area
OPALIZED WOOD GOODING • Clover Creek area
LATAH • Potlatch River Canyon, Kendrick area
OWYHEE • Few miles southeast of Hwy 95 at Idaho-Oregon state line in Coal Mine Basin (black opalized wood found in sandstone formation)
PROUSTITE BLAINE • Pilgrim Mine near head of Beaver Creek
BOISE • Banner Mining District
BUTTE • Hub Mine, Lava Creek Mining District
OWYHEE • War Eagle Mountain and Florida Mountain area near Silver City
SHOSHONE • Big Creek area
PETRIFIED WOOD CUSTER • Willow Creek Road south of Challis off US 93A
• Malm Gulch area
LINCOLN • Clover Creek
OWYHEE • West of DeLamar off Jordan Valley Road
• Middle reaches East Fork of Bruneau River
• 9 miles south of Bruneau east of US 51
• Sands Basin
WASHINGTON • Manns Creek area near Weiser
• Sage Creek near Weiser
• Crane Creek area
PETRIFIED WOOD – BLACK OWYHEE • Coal Mine Basin on US 85 south of Marsing
• Middle reaches East Fork Bruneau River 9 miles south of Coal Mine Basin on US 85 south of Marsing
• Clover Creek area
WASHINGTON • Sage Creek northwest of Weiser
PYRITE BLAINE • Hailey Gold Belt
BOISE • Quartzburg area
LEMHI • Mackinaw Mining District
SHOSHONE • Coeur d’Alene Mine District
QUARTZ – CRYSTALS BLAINE • Pole Creek tributary of Little Wood River
IDAHO • Near Warren
OWYHEE • At mines near Silver City
SHOSHONE • On O’Donnell Creek near Stocking Meadows
VALLEY • Green Mountain area
QUARTZ – CLUSTERS SHOSHONE • Gem, Burke, Murray and Delta areas
QUARTZ – SMOKEY ELMORE • Dismal swamp northwest of Rocky Bar
LEMHI • Along Bandy Creek
VALLEY • Paddy Flats, Big Creek near Cascade
QUARTZ – GEODES CUSTER • Upper Valley of Lost River
OWYHEE • DeLamar Silver Mine area
WASHINGTON • Northwest of Weiser
QUARTZ – PSEUDOMORPHIC BUTTE • Lava Creek Mining District
OWYHEE • War Eagle and Florida Mountain areas near Silver City
RHODOCHROSITE KOOTENAI • Conjecture Mine south of Lakeview (REMARKS: PINK)
LEMHI • Blackbird Mining District and Kitty Burton Mine in Indian Creek District
RHODONITE ADAMS • South of New Meadows
RUBIES ADAMS • Placer deposits near New Meadows in Adams and Valley counties
CLEARWATER • Clearwater Drainage near Pierce
OWYHEE • DeLamar – Silver City area
VALLEY • Placer deposits near New Meadows in Adams and Valley counties
SAPPHIRES ADAMS • Rocky Flat area near New Meadows
CLEARWATER • Rhodes Creek near Pierce
• Orofino Creek near Pierce
VALLEY • East slope of Brundage Mountain
SILLIMANITE
Fibrolite
LEMHI • Salmon River below Salmon
NEZ PERCE • Clearwater River Valley above Lewiston
• Big Eddy of Clearwater River above Spaulding
STAUROLITE BENEWAH • 5 miles up Carpenter Creek from junction with St. Maries River
SHOSHONE • St. Joe Basin and along St. Joe – Clearwater Divide
STILBITE ADAMS • Blue Jacket Claim, Seven Devils Mining District
BLAINE • Minnie Moore Mine near Bellevue
CUSTER • North side of Galena Summit
THULITE
Pink-colored Zoisite
ADAMS • Seven Devils Mining District
THUNDER EGGS – AMETHYST LINED
WASHINGTON • Beacon Hill, Hog Creek, Weiser area
THUNDER EGGS – QUARTZ LINED BUTTE • Antelope Creek, Arco area
• Road Creek, Arco area
TWIN FALLS • Rabbit Springs, US 93 Idaho-Nevada border
TOPAZ ELMORE • Dismal Swamp 9 1/2 miles northwest of Rocky Bar
TOPAZ – BLUE VALLEY • Along tributary of Paddy Creek in Paddy Flat area on Gold Fork Creek
• Donnelly area
TOPAZ – YELLOW CLARK • Camas Creek
TOURMALINE BLAINE • South flank Hyndman Peak
BOISE • Boise Basin area
CLEARWATER • Pierce area
LATAH • Avon area
LEMHI • Blackbird Mining District
VALENCIANITE
Adularia
CUSTER • Yankee Fork District
LEMHI • Gravel Range and Parker Mountain District
OWYHEE • War Eagle and Florida Mountain near Silver City
WILLOWHITE ADA • Longhair Mine north of Eagle
ZEOLITES
CUSTER
• Various locations
An interesting group of hydrated aluminous silicates.  Occurs as amygdular fillings in vesicles in basalt or amiosite flows; also as geode filling.  Thought deposited by hot waters at time of cooling of magmas.  Various locations in Owyhee and Custer counties.
OWYHEE • Various locations
ZIRCON IDAHO • Streams draining Idaho batholith, principally the American River near Elk City
ZOISITE (FOSSILS) ADAMS • Seven Devils Mining District
ZOISITE (FOSSILS)
CAMBRIAN
BONNER • In limy rock along southeast side of Pend Oreille Lake
GOODING • West rim of Snake River Canyon near Hagerman
ZOISITE (FOSSILS)
MARINE
OWYHEE • 9 miles south of Bruneau and to right of US 51
ZOISITE (FOSSILS)
TEMPSKYA
BONNEVILLE • 13 miles northwest of Hermans on Willow Creek
ZOISITE (FOSSILS)
TRILOBITE
VALLEY • South Fork of Gold Creek
ZOISITE (FOSSILS)
GRAPTOLITES AND INVERTEBRATES
BLAINE • Trail Creek east of Sun Valley
CUSTER • Shelves of Lost River Range
• Bayhorse area north of Clayton
ZOISITE (FOSSILS)
MOLLUSKS
CUSTER • Bayhorse area
ZOISITE (FOSSILS)
FISH
CUSTER • Lost River Range near Mackay
ZOISITE (FOSSILS)
MASTODON & MAMMOTH
LATAH • In sediments of Snake River Plain as far north as Palouse Hills