Name/Title
CreediteEntry/Object ID
2009.62.240Description
Chemical Composition: Ca3Al2(SO4)(OH2)F8*2H2O
Crystal System: Monoclinic System
Description: Common Name:Creedite
Chemistry:Ca3Al2(SO4)(OH2)F8*2H2O
Class:Sulfates
Subclass:
Group:
Location:Francisco Portillo,West Camp,Santa Eulalia District.Mun.De Aquiles Serdan,Chihuahua,Mexico
DESCRIPTION:Creedite is a rather rare sulfate found as an accessory to highly oxidized ore bodies. It can be confused with cobalt-rich adamite when its color is purple. It lacks adamite's luster, though, and adamite's dome termination is not slanted, as creedite's is. Creedite's purple color is attractive and its crystal form is unique, making creedite a nice mineral collection addition.
PHYSICAL CHARACTERISTICS:
• Color is white, colorless and purple.
• Luster is vitreous.
• Transparency crystals are transparent to translucent.
• Crystal System is monoclinic; 2/m
• Crystal Habits include prismatic crystals with a dome termination whose top edge is slanted with respect to length. Also acicular crystals in radiating groups.
• Cleavage is perfect in one direction.
• Fracture is uneven.
• Hardness is 4.
• Specific Gravity is approximately 2.7+ (average for translucent minerals)
• Streak is white.
• Associated Minerals are limonite, cassiterite, adamite and vanadanite.
• Other Characteristics: color if present is unevenly distributed through the crystals.
• Notable Occurrences include Mapimi, Mexico; Colquiri, Bolivia and Colorado, USA.
• Best Field Indicators are crystal habit, associations and locality.
Fracture: Uneven
Hardness: 4 Fluorite
Luster: Vitreous
Rock Type: Metamorphic
Specific Gravity: 2.7
Streak: WhiteCollection
RAGM Mineral CollectionAcquisition
Accession
2009.62Source or Donor
Museum Collection of MineralsAcquisition Method
DonationDimensions
Width
4 inDepth
4 inLength
6 inLocation
Location
Shelf
CS-I-2Room
Curation StorageBuilding
Crater Rock MuseumDate
January 31, 2024
