Benitoita
Benitoita is a mineral with formula BaTi(Si₃O₉), in the Silicatos (Ciclosilicatos) group. This specimen comes from California State Gem Mine, Santa Rita Peak, San Benito County, California, Estados Unidos.
Description
Five violet-blue benitoite crystals on an elongated matrix with white natrolite. One large crystal with a well-defined triangular outline dominates the specimen. The crystals show whitish lines and visible internal fractures. A few black prismatic neptunite crystals complete the specimen.
About Benitoita
To expose San Benito benitoite, preparators commonly remove part of the natrolite with hydrochloric acid. It has been California’s official state gemstone since 1985. One study proposed an age of about 12 million years, still tentative, compared with 100–160 million years for the host schist. Benitoite grew before natrolite filled the fractures and enclosed the crystals. Its association with neptunite is a classic of this locality.
About the locality
Benitoite’s type locality: the classic San Benito mine, also known as the Dallas Gem Mine. The 1907 discovery led to mining for both gemstones and mineral specimens. The mineralization occurs in natrolite veins in glaucophane schist within a serpentinite body. Collector’s Edge worked the deposit and accumulated material in the early 2000s and reclaimed the site in 2004. That does not mean that everything available today comes from old collections: Benitoite Mining Company offers searches through mine material brought to its Coalinga site. The original mine is not open to the public.
Technical data
- Catalogue No.
- 0693
- Composition
- BaTi(Si₃O₉)
- Name
- Benitoita
- Group
- Silicatos (Ciclosilicatos)
- Category
- Meritum Persé
- Matrix
- Natrolita
- Associations
- Neptunita
- Mine
- California State Gem Mine
- District / Municipality
- Santa Rita Peak
- Province
- San Benito County
- Region
- California
- Country
- Estados Unidos
- Size (cm)
- 4 x 2 x 1.5
- Weight
- 7.1 g
- Ex-collection
- Francisco Muñoz Leiva
- Etymology
- The name refers to San Benito, California, where the mineral was found. George D. Louderback described it in 1907.
- Quality
- Notable
- Value trend
- Estable
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