Barite with Cinnabar

Object/Artifact

-

Crater Rock Museum

Name/Title

Barite with Cinnabar

Entry/Object ID

2004.1.16

Description

Assemblage Zone: oxidation zone Chemical Composition: BaSO4 Crystal System: Orthorhombic System Description: Common Name: Barite with Cinnabar "BARITE" Chemistry: BaSO4, Barium Sulfate Class: Sulfates Group: Barite "CINNABAR" Chemistry: HgS, Mercury Sulfide Class: Sulfides and Sulfosalts Location: Baia Sprie Mine, Baia Sprie Maramures County, Romania. Description: red crystals PHYSICAL CHARACTERISTICS OF BARITE: Color is variable but is commonly found colorless or white, also blue, green, yellow and red shades. Luster is vitreous. Transparency crystals are transparent to translucent. Crystal System is orthorhombic; 2/m 2/m 2/m Crystal Habits include the bladed crystals that are dominated by two large pinacoid faces top and bottom and small prism faces forming a jutting angle on every side. There are many variations of these faces but the flattened blades and tabular crystals are the most common. If the pinacoid faces become diminished or are absent, the resulting prismatic crystal has a rhombic cross section. Also scaly, lamellar, and even fiberous. Cleavage is perfect in one direction, less so in another direction. Fracture is conchoidal. Hardness is 3 - 3.5 Specific Gravity is approximately 4.5 (heavy for translucent minerals) Streak is white. Associated Minerals are numerous but significant associations have been with chalcopyrite, calcite, aragonite, sulfur, pyrite, quartz, vanadinite, cerussite and fluorite among many others. Other Characteristics: green color in flame test (see above). Best Field Indicators are crystal habit, flame test and density. PHYSICAL CHARACTERISTICS OF CINNABAR: Color is a bright scarlet or cinnamon red to a brick red. Luster is adamantine to submetallic in darker specimens. Transparency crystals are translucent to transparent. Crystal System is trigonal; 32 Crystal Habits: individual, well formed, large crystals are scarce; crusts and crystal complexes are more common; may be massive, or in capilary needles. Crystals that are found tend to be the six sided trigonal scalahedrons that appear to have opposing three sided pyramids. It also forms modified rhombohedrons, prismatic and twinned crystals as discribed above. Cleavage is perfect in three directions, forming prisms. Fracture is uneven to splintery. Hardness is 2 - 2.5. Specific Gravity is approximately 8.1+ (very heavy for a non-metallic mineral) Streak is red Associated Minerals are realgar, pyrite, dolomite, quartz, stibnite and mercury. Other Characteristics: silghtly sectile and crystals can be striated. Best Field Indicators are crystal habit, density, cleavage, softness and color. Fracture: conchoidal - uneven Hardness: 3 Calcite Luster: Vitreous Occurrence: Occurs as gangue mineral in hydrothermal veins, in druses, as concretions in sandstones and other sedimentary rocks. Rock Type: Sedimentary Specific Gravity: 4.5 Streak: red Texture: Crystalline Variety: Barite is a common mineral and makes very attractive specimens. It often is an accessory mineral to other minerals and can make a nice backdrop to brightly colored crystals. At times bladed or tabular crystals of Barite form a concentric pattern of increasingly larger crystals outward. This has the appearance of a flower and when colored red by iron stains, these formations are called "Desert Roses". Because Barite is so common, it can be confused for other minerals. Celestite (SrSO4) has the same structure as barite and forms very similar crystals. The two are indistinguishable by ordinary methods, but a flame test can distinguish them. By scrapping the dust of the crystals into a gas flame the color of the flame will confirm the identity of the crystal. If the flame is a pale green it is barite, but if the flame is red it is celestite. The flame test works because the elements barium (Ba) and strontium (Sr) react in the flame and produce those colors. Cinnabar is a colorful mineral that adds a unique color to the mineral color palette. Its cinnamon to scarlet red color can be very attractive. Well shaped crystals are uncommon and the twinned crystals are considered classics among collectors. The twinning in cinnabar is distinctive and forms a penetration twin that is ridged with six ridges surrounding the point of a pryamid. It could be thought of as two scalahedral crystals grown together with one crystal going the opposite way of the other crystal. Cinnabar was mined by the Roman Empire for its mercury content and it has been the main ore of mercury throughout the centuries. Some mines used by the Romans are still being mined today. Cinnabar shares the same symmetry class with quartz but the two form different crystal habits

Collection

Suomynona Mineral Collection

Acquisition

Accession

2004.1

Source or Donor

Suomynona Mineral Collection

Acquisition Method

Donation

Dimensions

Width

5 in

Depth

2-1/2 in

Length

7-1/2 in

Weight

3.05 oz

Dimension Notes

Dimension taken at widest points

Location

Location

Container

right

Drawer

bottom tier

Shelf

south side, south side

Wall

center

Hallway

Discovery Hall

Building

Crater Rock Museum

Category

Permanent

Moved By

Wendy Mondry

Date

December 26, 2008

Location

Container

Left

Drawer

Top Shelf

Shelf

Left

Cabinet

Case # 35

Wall

East

Building

Freida Smith Hall

Category

Permanent