It produces a variable luster that can be nearly metallic in one specimen to vitreous in another. Color is usually golden yellow or yellowish brown, but also greenish brown specimens are found. Luster is vitreous or submetallic to metallic, can be pearly on cleavage surfaces. Also found in lamellar massives.
Cleavage is perfect in one direction.
Fracture is uneven. Hardness is 3. Specific Gravity is 3.3 - 3.4 Streak is yellowish white. Associated Minerals are quartz , feldspars , nepheline , micas and aegirine . Best Field Indicators brittleness, cleavage, color, luster and localities.