Name/Title
HeulanditeEntry/Object ID
2004.1.53Description
Assemblage Zone: pegmatite dikes
Chemical Composition: (Ca, Na)2 - 3Al3(Al, Si)
Crystal System: Monoclinic System
Description: Common Name: Heulandite
Group Name: Zeolites
Chemistry: (Ca,Na,K)Al10(Al,Si)Si29 O80*25H2O
Location: Rats Nest claim, Idaho USA
Description: Grayish outer shell with white, undnerneath and light pink crystals inside.
PHYSICAL CHARACTERISTICS:
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.
Associated Minerals are extensive and include quartz, calcite, apophyllite, barite, pyrite, prehnite, pollucite, tourmaline, scolecite, analcime, chabazite, ferrierite, mordenite, laumontite, natrolite, stilbite and other zeolites.
Best Field Indicators are crystal habit, density, cleavage, luster and associations.
Fracture: uneven
Hardness: 4 Flourite
Luster: Vitreous
Occurrence: 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.
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: Sedimentary
Specific Gravity: 2.1
Streak: white
Variety: n/aCollection
Suomynona Mineral Collection, Suomynona CollectionAcquisition
Accession
2004.1Source or Donor
Suomynona Mineral CollectionAcquisition Method
DonationDimensions
Width
10 inDepth
10 inLength
15 inDimension Notes
Dimension taken at widest pointsLocation
Location
Container
LeftDrawer
BottomShelf
Left, LeftWall
NorthBuilding
Freida L Smith HallCategory
PermanentMoved By
Scott LonganDate
August 25, 2009Location
Container
RightDrawer
BottomShelf
RightCabinet
Case # 41Wall
SouthRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
Permanent
