Name/Title
HeulanditeEntry/Object ID
2009.62.204Description
Chemical Composition: Hydrated Calcium Sodium
Crystal System: Monoclinic System
Description: Common Name: Heulandite
Chemistry: Ca, Na)2 - 3Al3(Al, Si)2Si13O36 - 12H2O,
Class: Zeolites
Heulandite is one of the most common and one of the most well known members of the Zeolite Group. It can have a nice pearly luster and lovely colored hues. It forms wonderfully complex and quite unique crystals and is often associated with other rare and beautiful minerals. Rarely are the larger crystals transparent, but they always have a certain depth of translucency. Heulandite forms large crystals in the petrified bubbles (called vesicles) of volcanic rocks that have had a slight amount of metamorphism. Huelandite occurs in other environments but does not generally form large well shaped crystals in those situations. Heulandite gets its name in honor of John Henry Heuland, a British mineral collector and dealer.
Color is colorless, white, gray, green, pink, yellow, red, brown and black.
Luster is vitreous to pearly on the most prominent pinacoid face and on cleavage surfaces.
Transparency: Crystals are transparent but most commonly translucent.
Crystal System is monoclinic; 2/m
Crystal Habits include blocky crystals described as diamond-shaped, trapezoidal and old fashioned coffin shape with the two faces of a pinacoid usually prominent. Crystals are often modified by secondary faces with pairs of triangular faces very common. Prismatic and acicular forms are also known and are difficult to identify as heulandite. In aggregate specimens this face can be oriented upward producing a crust of curved pearly faces or it can be oriented to the side where the tops of the crystals jut out like the roof tops of a suburban community. Crystals can be simple or complexly modified by a variety of prism and pinacoid faces.
Cleavage is perfect in one direction parellel to the prominent pinacoid face.
Fracture is uneven.
Hardness is 3.5 - 4, maybe softer on cleavage surfaces.
Specific Gravity is approximately 2.1 - 2.3 (very light due to the open channels and high water content).
Streak is white.
Fracture: uneven
Hardness: 4 Fluorite
Luster: Vitreous
Occurrence: Notable Occurrences are wide spread and include Poona and Nasik Districts, India; Iceland; New Jersey; Washington; Boron, California; Patterson, New Jersey; Arizona and Oregon, USA; Nova Scotia and Quebec, Canada; Iran; Sardinia, Italy; Rio Grande do Sul and Goias, Brazil; New South Wales and Phillip Island, Victoria, Australia; New Zealand; Kola Peninsula, Russia; Scotland and Rhone Valley, Switzerland.
Rock Type: Igneous
Specific Gravity: 2.1 - 2.3
Streak: WhiteCollection
RAGM Mineral CollectionLocation
Location
Display Case
DS-6Room
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
May 24, 2023Notes
Added current location
