Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Acicular - Occurs as needle-like crystals.
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Habit:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Hardness:
3-4 - Calcite-Fluorite
Luster:
Vitreous (Glassy)
Streak:
light brown
Optical Properties of Eggletonite
Gladstone-Dale:
CI meas= 0.045 (Good) - where the CI = (1-KPDmeas/KC) CI calc= 0.059 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2117,KPDmeas= 0.2147,KC= 0.2249 Ncalc = 1.62 - 1.63