Name/Title
FluorapophylliteEntry/Object ID
2004.1.9Description
Assemblage Zone: pegmatitic dikes
Chemical Composition: K1Ca4S18O20(F,OH)
Crystal System: Triclinic System
Description: Common Name: Fluorapophyllite
Chemistry: (K, Na)Ca4 Si8O20(F,OH) - 8H2O
Class: Silicates
Subclass: Phyllosilicates
Group: Apophyllite
Found at Jalgaon District, Maharashtra, India
This speciman has large pale green crystal surrounded by peach colored stilbite crystals on the matrix
THE PHYSICAL CHARACTERISTICS OF APOPHYLLITE:
Color is clear, white, green, yellow, pink, violet or rarely brown.
Luster is vitreous to pearly on cleavage surfaces.
Transparency: Crystals are transparent to translucent.
Crystal System is tetragonal; 4/m 2/m 2/m; natroapophyllite is orthorhombic, 2/m 2/m 2/m.
Crystal Habits include four sided prisms (with a square cross-section) truncated with either a steep four sided pyramid or a pinacoid termination or both. If the pyramids are missing, the crystals can look cubic. Rarely are the prisms missing, but if they are, crystals could appear octahedral because of the four sided pyramids. The faces of the pyramids do not lineup with the prism faces but with their edges, therefore the pyramid faces have four edges and appear diamond shaped instead of triangular like the pyramid faces of quartz. Rare tabular hydroxyapophyllite crystals are also known.
Cleavage is perfect in one direction (basal).
Fracture is uneven.
Hardness is 4.5 - 5.
Specific Gravity is approximately 2.3 - 2.4 (lighter than most translucent minerals).
Streak is white.
Other Characteristics: Prism faces are striated lengthwise, some specimens are fluorescent and crystals will flake when heated.
Associated Minerals are prehnite, quartz, heulandite, stilbite, natrolite, analcime, datolite, babingtonite, cavansite, calcite, idocrase, wollastonite, kinoite, gyrolite and many other zeolites.
Best Field Indicators are crystal habit, striations, associations, environment of formation, cleavage and luster on cleavage surfaces.
Fracture: Brittle, uneven
Hardness: 5 Apatite
Luster: Pearly
Occurrence: Occurs in vesicles in volvanic rocks, in druses and lining fissures in ore veins or cavities in silicate rock.
A secondary mineral in amygdules or druses in basalts. A late-stage mineral in some mineral deposits.
Apophyllite specimens are found in ancient lava and basalt flows. The crystals grow in the now solid cavities, called amygdules or vesicles, formed by air bubbles when the rock was molten. Apophyllite is also found in the voids in the contact metamorphic zone limestones that surround intrusive rocks.
Rock Color: Light
Rock Type: Igneous
Specific Gravity: 2.3 - 2.4
Streak: White
Texture: Crystaline
Variety: Fluorapophyllite is by far the most abundant and colorful of the three and is usually what is referred to when a specimen is just labeled apophyllite. Hydroxyapophyllite is also relatively common, but specimens typically lack any color and are limited to pseudo-cubic crystal habits. The natroapophyllite is quite rare and is found at only a few localities. Its typical brown color can help distinguish it from its close cousins. Natroapophyllite, by virtue of its more significant chemical and symmetrical difference, is truly a distinct mineral. Fluorapophyllite and hydroxyapophyllite however are a different story. The two are different minerals only because of the difference in the percentage of fluorine to hydroxyl ions. They represent the end members of a series that could be called the apophyllite series. The name apophyllite persists however and its usage is widespread, especially when distinguishing the true identity of specimens is difficult. Most mineral guide books list apophyllite as a single mineral and the rest of this discussion will deal with apophyllite in general.Collection
Suomynona Mineral Collection, Suomynona CollectionAcquisition
Accession
2004.1Source or Donor
Suomynona Mineral CollectionAcquisition Method
DonationDimensions
Width
5-1/2 inDepth
5 inLength
8 inWeight
7.34 ozDimension Notes
Dimension taken at widest pointsLocation
Location
Display Case
DS-6Room
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
May 24, 2023Notes
Added current locationLocation
Container
RightWall
WestRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Steve MillerDate
May 17, 2013Location
Container
leftDrawer
bottom tierShelf
north side, north sideWall
centerHallway
Discovery HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Wendy MondryDate
December 26, 2008Location
Container
RightCabinet
Case#41Wall
WestRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
Permanent