Name/Title
ThenarditeEntry/Object ID
2014.1.46Description
Chemical Composition: Al(OH)3
Crystal System: Hexagonal System
Description: Common Name: Thenardite
Chemistry: Na2SO4
Group: Sulfates
Location: Mexico
Description: Small grouping of flat, rectangular crystals. Color is gray.
Physical Charateristics:
Color is typically gray, white, colorless or brownish white or yellowish white.
• Luster is vitreous, pearly to resinous.
• Transparency: Crystals are transparent to translucent.
• Crystal System is orthorhombic: 2/m 2/m 2/m.
• Crystal Habits include tabular, dipyramidal, flattened, diamond-shaped crystals; often intergrown. Twins form arrowhead like crystals and crossed interpenetration twins. Also as crusts, granular and as massive rock forming beds.
• Cleavage is perfect in one direction (pinacoidal).
• Fracture is uneven to hackly or splintery.
• Hardness is 2.5 - 3.
• Specific Gravity is approximately 2.7 (average for translucent minerals).
• Streak is white.
• Other Characteristics: Easily soluble in water, has a salty taste, is fluorescent white in shortwave UV and yellow-green in longwave UV and can color a flame yellow (for sodium).
• Associated Minerals include halite, mirabilite, gypsum, glauberite, trona, blodite, alunite, picromerite, sborgite, borax and other borate and non-marine evaporite minerals.
• Notable Occurrences include several California sites such as Searles Lake, San Bernardino County; Soda Lake, San Luis Obispo County; Bertram deposit, Imperial County and Furnace Creek district, Inyo County; as well as Camp Verde Yavapi County in Arizona and sites in Nevada, USA; Espartinas, Madrid Province, Spain; Siberia, Russia; Mt Etna, Sicily, Italy; Chile; Kazakhstan and Canada.
• Best Field Indicators are crystal habit, environment of formation, associations, cleavage, taste and fluorescence.
Hardness: 7 Quartz
Rock Type: SedimentaryCollection
RAGM Mineral CollectionAcquisition
Accession
2014.1Source or Donor
Crater Rock Museum (unknown donors)Acquisition Method
GiftDimensions
Height
2-1/8 inWidth
1-3/8 inLength
2-1/4 inLocation
Location
Display Case
FS-11Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
December 27, 2023