Topaz Mountain is a summit in the

Thomas Range The Thomas Range is a mountain range of north central Juab County of western Utah, United States. Topaz Mountain is in the southern part of the range and Spor Mountain lies to the southwest.''Utah Atlas & Gazeteer,'' DeLorme, 9th ed., 2014, pp. ...

of Utah, east of the Thomas

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

. The summit and surrounding area are known for their abundances of semiprecious minerals including

topaz Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al Si O( F, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can mak ...

red beryl Red beryl, formerly known as bixbite and marketed as red emerald or scarlet emerald, is an extremely rare variety of beryl as well as one of the rarest minerals on Earth. The gem gets its red color from manganese ions embedded inside of beryllium ...

and

opal Opal is a hydrated amorphous form of silica (SiO2·''n''H2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline forms ...

Geology and geography

Topaz Mountain is part of the Thomas Range in

Juab County, Utah Juab County ( ) is a county in western Utah, United States. As of the 2010 United States Census, the population was 10,246. Its county seat and largest city is Nephi. Juab County is part of the Provo–Orem, Utah Metropolitan Statistical ...

, approximately 36 miles Northwest of

Delta, Utah Delta is the largest city in Millard County, Utah, United States. It is located in the northeastern area of Millard County along the Sevier River and is surrounded by farmland. The population was 3,436 at the 2010 census. History Delta was ori ...

. It lies on publicly owned land managed by the

Bureau of Land Management The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands. Headquartered in Washington DC, and with oversight over , it governs one eighth of the country's la ...

(BLM). Collection of rocks and mineral is permitted there and, as a result, the area is frequented by amateur and professional

rock hound Amateur geology or rock collecting (also referred to as rockhounding in the United States and Canada) is the non-professional study and hobby of collecting rocks and minerals or fossil specimens from the natural environment.Sinkankas, John. Minera ...

s. Red beryl in topaz-bearing

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...

, and water-laid rhyolitic

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

, was known on Topaz Mountain since 1905. This

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

age tuff is found throughout the Thomas Range. In 1959, beryllium deposits (

bertrandite Bertrandite is a beryllium sorosilicate hydroxide mineral with composition: Be4Si2O7(OH)2. Bertrandite is a colorless to pale yellow orthorhombic mineral with a hardness of 6-7. It is commonly found in beryllium rich pegmatites and is in part an ...

) were found overlying this tuff on Spor Mountain.

Minerals

Topaz

Topaz Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al Si O( F, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can mak ...

is a semiprecious gemstone that occurs as very hard, transparent crystals in a variety of colors. It is naturally amber-colored, but becomes colorless after exposure to sunlight. Topaz forms within cavities of the volcanic rock

, from eruptions that occurred during the Tertiary Period six to seven million years ago. Topaz is embedded in the rhyolite rock, and also found loose on the slopes and arroyos.

Red beryl

Red beryl Red beryl, formerly known as bixbite and marketed as red emerald or scarlet emerald, is an extremely rare variety of beryl as well as one of the rarest minerals on Earth. The gem gets its red color from manganese ions embedded inside of beryllium ...

, a rare mineral found at Topaz Mountain, occurs as small crystals, often attached to other mineral crystals. It is estimated that one red beryl crystal is found for every 150,000 diamonds. Prices for top quality natural red beryl can be as high as $10,000 per carat for faceted stones. The ground around Topaz Mountain

Other minerals

A variety of other minerals are found at Topaz Mountain including

garnet Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different s ...

amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος ''amethystos'' from α- ''a-'', "not" and μεθύσκω (Ancient Greek) / μεθώ (Modern Greek), "intoxicate", a reference to the belief that t ...

, pseudobrookite and

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

References

External links

* * {{cite summitpost , id=745813 , name=Topaz, Juab, Utah Mountains of Juab County, Utah