Page 30 - Petrophysics 2E

TABLE 1.4
MINERAL COMPOSITIONS AND DESCRIPTIONS. PARENTHESES THE FORMULAS
IN
MEAN THAT THE ELEMENTS ENCLOSED MAY BE PRESENT IN VARYING AMOUNTS.
Agate (Chalcedony)-SiO2: silicon dioxide; variable colors; waxy luster; H = 7*.
Anhydrite-CaS04: calcium sulfate; white-gray; H = 2.
Apatite-Cag(PO4)gF: fluorapatite; H = 4.
Asbestos (Serpentine)-Mg6Si4010(0H)~: hydrous magnesium silicate; light
green to dark gray; greasy or waxy; H = 3.
Augite (Pyroxene group)-(Ca, Na)(Al, Fe2+, Fe3+, Mg)(Si, Al)zO6: Alkali, ferro-
magnesium, aluminum silicates; dark green to black; exhibits cleavage; large,
complex group of minerals; H = 5.
Barite-BaS04: barium sulfate; white, light blue, yellow, or red; pearly luster,
H = 3.
Beryl-Be3d2Si6018: clear beryl forms the blue-green aquamarine and green
emerald gems; exhibits cleavage. Beryl is an ore of the element beryllium;
H = 7-8.
Biotite (Mica)-K(Fe, Mg)3(AlSi3010)(OH)z: hydrous potassium, ferro-
magnesium, aluminum silicate; dark green to black (black mica); vitreous;
exhibits cleavage; rock-forming mineral; H = 3.
Calcite-CaCO3: calcium carbonate; colorless or white to light brown, vitreous;
effervesces in dilute HC1; H = 3.
Celestite-SrS04: strontium sulfate; colorless; H = 3.
Chalk-CaC03 : calcite; white; soft fine-grained limestone formed from
microscopic shells; effervesces with dilute HCl; H = 2-3.
Chlorite-(Al, Fe, Mg)6(Al, Si)4010(OH)8: hydrous ferro-magnesium, aluminum
silicate; shades of green (green mica); exhibits cleavage; rock-forming mineral;
H = 3.
Cinnabar-HgS: mercury sulfide; red to brownish-red; luster is dull. Only
important ore of mercury; H = 2.5.
Cordierite-Al4(Fe, Mg)z Si5 0 18 : ferro-magnesium aluminum silicate; blue;
vitreous; H = 7.
Corundurn-Al203: red varieties are rubies and other colors are known as
sapphire; H = 9.
Diatomite-Si02 : silica; white; formed from microscopic shells composed of
silica; distinguished from chalk by lack of effervescence with dilute HCl;
H = 1-2.
D0lomite-CaMg(CO3)~: calcium-magnesium carbonate; pink or light brown,
vitreous-pearly; effervesces in HCl if powdered; H = 3.
Feldspar (Orthoclase, Potassium feldspar)-KalSi308: white to pink; vitreous;
large crystals with irregular veins; exhibits cleavage; rock-forming mineral;
H = 6.
Feldspar (Plagioclase)-CaAl~Si208 and NaAlSi308(dbite): calcium and sodium
aluminum silicate; white to green; vitreous; exhibits cleavage; rock-forming
mineral; H = 6.
Fluorite-CaF2: calcium fluorite; H = 4.
Galena-PbS: lead sulfide; lead-gray; bright metallic luster; lead ore; H = 2.5.
*H = Hardness; defined in the Glossary.
Continued