Fine crystals of phenakite can be perfectly clear and with good hardness, rarity and lack of good cleavage, although somewhat lacking in color and fire, make good choices for gemstones. Color is usually colorless or white but can be tinted yellow, brown and pink. Luster is vitreous. Transparency crystals are transparent to translucent. Twinning is common and forms penetration twins Cleavage in poor in three directions.
Fracture is conchoidal.
Streak is white. Prism faces striated lengthwise and index of refraction is approximately 1.66. Associated Minerals are topaz , cassiterite , quartz , calcite , hematite , feldspars , apatite , fluorite , beryl especially emerald , chrysoberyl , bertrandite and some sulfides . Best Field Indicators are crystal habit, striations, enviroment and hardness.