The Mineral Identification Key Copper, Michigan, Seaman Museum specimen

Table IIC-2a: Nonmetallic Luster; Streak Not Colored; Hardness 2½ to 3; Cleavage Not Prominent; Splinter Will Fuse in a Candle Flame. [Previous Table [Next Table
Fusibility Color Hardness Luster Name System Habit SG Notes
Swells and fuses to a glassy
globule in a candle flame
Usually Snow-white; Colorless to White or Greyish-white, may be tinted other colors 2 to 2½ Vitreous to resinous BORAX Na2B4O5(OH)4.8H2O Monoclinic Usually in crystalline or granular masses, crystals short
prismatic to somewhat tabular, flattened prisms
1.7 Dissolves in water, has a sweetish, alkaline taste
Small splinters fusible in a candle flame Colorless to White, may be tinted other colors Vitreous to greasy, has an unusual greasy translucence CRYOLITE 
Monoclinic Usually massively
crystalline to coarse granular, crystal rare and usually pseudo-cubic
2.95 to 3.0 White streak; small clear fragments seem to disappear when placed in water (nearly identical refractive-index)
Small splinters fusible in a candle flame Colorless to White or Greyish-White, may be tinted other colors 3 to 3½ Adamantine to vitreous, may be resinous on cleavage surfaces, may also appear submetallic when dark colored CERUSSITE (Aragonite Group)
Orthorhombic Usually as crystalline to granular masses, crystals usually tabular in platy clusters or aggregates, may be prismatic, rarely acicular (habit widely varied) 6.55 Cleavage distinct in one direction and good in another, but rarely seen, effervesces in warm acid. Massive material difficult to distinguish from anglesite without testing for CO3 vs. SO4. Also see strontianite

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