Beryl Helidor
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Formula:   Be3Al2(Si6O18)   mineral photo

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Crystal:   Hexagonal  
Hardness:   7.5-8  
Spec. Gr.:   2.66-2.8  
Streak:   White  
Cleavage:   Imperfect basal  
Location:   Itingua, Minas Gerais, Brazil  

Heliodor (golden beryl) crystals are uncommon world-wide. Yellow beryl crystals are reported from Skardu, Gilgit, Pakistan; Tokoyawa, Ural Mts., Russia (golden variety); and Wolodarsk, Wolynsky, Ukraine. The latter locality has produced the greatest number of greenish-yellow beryl crystals from anywhere in recent years. These crystals are reported from extremely large crystal pockets up to 20 meters in size, which are frequently filled with fine loose muscovite crystals and clay, as well as loose crystals of lepidolite, protolithionite, quartz and topaz. The crystals of heliodor are heavily etched and are of gem quality. They are lustrous and range in size from 2-20 cm. Heliodor from deposits in Minas Gerais, Brazil are tabular, some with excellent terminations, and are found sparingly in small sizes in pegmatites which produced other beryl crystals. Many years ago it was believed that the wearer of the stone was rendered unconquerable and at the same time amiable, while his intellect was quickened and he was cured of laziness.

Bibliography: Mineralogical Record, V18, no. 3, pg. 243-244.

Kunz, George Frederick, The Curious Lore of Precious Stones, pg. 243-244.

University of California, Santa Barbara—Department of Earth Science
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