The Mineral KIDWELLITE

Chemistry: NaFe9(PO4)6(OH)10 - 5H2O, Hydrated Sodium Iron Phosphate Hydroxide.
Class: Phosphates
Uses: Only as mineral specimens.
Specimens

Kidwellite is a rare, typically yellow-green phosphate mineral. Its color is distinctive as well as its compact encrusting crystal habit. It is found in phosphate deposits with other rare phosphates from classic localities such as Cornwall, England.

PHYSICAL CHARACTERISTICS:

Color is yellow-green, pale green or yellow.
Luster is vitreous.
Transparency: Specimens are translucent to transparent.
Crystal System is monoclinic; 2/m
Crystal Habits include compact encrusting aggregates, also massive and fibrous.
Cleavage is poor.
Fracture is fibrous.
Hardness is 3 - 4
Specific Gravity is approximately 2.5 - 3.4 (average to slightly above average).
Streak is green.
Associated Minerals include strengite, beraunite, dufrenite, rockbridgeite and limonite.
Notable Occurrences include Cornwall, England and Coon Creek Mine, Polk County, Arkansas, USA.
Best Field Indicators are crystal habit, color, associations and streak.