APPLICATIONS: | Mineral specimens. |
ASSOCIATED MINERALS: | Olivine, biotite, nepheline, albite, apatite, serpentine, leucite and hornblende. |
CHEMICAL STRUCTURE: | (Ca, Na)(Mg, Fe, Al)(Al, Si)2 O6, Calcium Sodium Magnesium Iron Aluminum Silicate. |
CLASS: | Silicates. |
CLEAVAGE: | Perfect in two lengthwise directions at close to right angles. |
COLOR: | Dark green, brown and black. |
CRYSTRAL HABITS: | Short prismatic, rarely tabular crystals. The square cross section is distinctive in the prismatic crystals. Also compact, granular, columnar, lamellar and fibrous. |
CRYSTAL SYSTEM: | Monoclinic, 2/m. |
FIELD INDICATORS: | Crystal habit, associations, color, parting and cleavage. |
FRACTURE: | Uneven. |
GENERAL INFORMATION: | Basal parting is prominent. |
GEOGRAPHY: | Grand County, Colorado, St. Lawrence County, New York and Tillamook, Oregon, USA; Eifel, Germany; Mt. Vesuvius, Italy; France and Bohemian regions of Europe. |
GROUP: | Pyroxenes. |
HARDNESS: | 5 - 6. |
LUSTER: | Vitreous to submetallic and even dull. |
TRANSPARENCY: | Transparent to mostly translucent or opaque. |
SPECIFIC GRAVITY: | 3.2 - 3.6. |
STREAK: | Greenish white. |
SUBCLASS: | Inosilicates. |
