MMEW 2025 Rock and Mineral Answer Key.xlsx

	A	B	C	D	E	F	G	H
1	MINERALS
2	#	Color	Luster	Streak	Hardness	Cleavage*	Other notable properties	Mineral
3	3	colorless, white, yellow, grey, red, brown, blue, green	vitreous to earthy	white	3	perfect 3 directions at 75 degrees	effervesces (bubbles) in dilute HCl; double refraction	calcite
4	6	white, pink, brown, green	vitreous to pearly	white	6	2 directions at 90 degrees	grains can look streaky with small wavy lines	orthoclase (potassium feldspar, "k-spar")
5	7	colorless to almost any color	vitreous to greasy	white	7	none (conchoidal fracture)	hexagonal crystals are common	quartz
6	8	brassy yellow, can tarnish	metallic	greenish-black to black	6–6.5	none	cubic crystals, some striated (lined) faces	pyrite
7	11	copper to dark brown, greenish if oxidized	metallic	copper	2.5–3	none (hackly fracture)	malleable	copper
8	12	colorless, white, yellow, red, blue, brown	vitreous to waxy or dull	white	2.5	perfect 3 directions at 90 degrees	cubic crystals, salty taste	halite
9	13	dark grey to black	metallic or submetallic	dark grey	6	none (conchoidal fracture)	magnetic	magnetite
10	14	blue-grey, black, white	vitreous to pearly	white	6	2 directions at ~90 degrees	striations (parallel lines) on cleavage planes; some varieties have opalescence	plagioclase
11	15	colorless, green, yellow, brown, brown-red	vistreous to silky or pearly	white	2–2.5	1 perfect	mica; flexible, thin sheets	muscovite
12	16	very dark brown to black	vitreous to pearly	grey-brown to white	2.5–3	1 perfect	mica; flexible, thin sheets; hexagonal shapes sometimes	biotite
13	17	green to black	vitreous to dull	grey-green to brown	5–6	2 directions at ~90 degrees	stubby crystals, rectangular cross sections	pyroxene
14	18	green to black	vitreous to dull	greenish-black to black to white	5–6	2 directions at ~120 degrees	crystals can be splintery or fibrous	amphibole
15	19	green, black, yellow	vitreous	white	6.5–7	none (conchoidal fracture)	common in granular masses	olivine
16	22	dark red, brown, pink, green, yellow	resinous, vitreous, or dull	white	6.5–7.5	none	often occurs as 12- or 24-sided crystals (not elongate in any direction)	garnet
17	23	black to dark brown, red tarnish	metallic, submetallic, or earthy	red to red-brown	5.5–6.5 (softer if earthy luster)	none	can occur in many different forms	hematite
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19	IGNEOUS ROCKS
20	#	Color Index	Minerals	Texture	Rock Name	Origin
21	2	Lt to Med.	Quartz/Kspar/Amphibole/Biotite (Plagioclase)	Po-Ph	Granite	I or TS
22	3	Lt	Quartz/Kspar/Biotite (Amphibole)	Ph	Granite	I
23	4	Dark	None visible	A or Gl	Obsidian	E
24	5	Light	(Biotite)	A (Po)	Pumice	E (TS)
25	8	Med. To Dark	Amphibole (Plagioclase)	Po	Andesite	E or TS
26	9	Med.	Plagioclase/Amphibole/Biotitie (Pyroxene, Quartz)	Ph	Diorite	I
27	10	Dark	Olivine (Pyroxene)(Plagioclase)	Po, V, A	Basalt	E or TS
28	11	Med. To Dark	Pyroxene/Plagioclase (Olivine, magnetite)	Ph	Gabbro	I
29	12	Dark	Generally not visible	A, V	Scoria (vesicular basalt)	E
30	13	Dark	Olivine (Pyroxene)	Ph	Peridotite	I
31
32	METAMORPHIC ROCKS
33	#	Grain Size	Minerals; Structures Present	Rock Name
34	1	fine	too fine to tell; slaty cleavage	Slate
35	2	fine	(micas); slaty or schistose	Phyllite
36	4	med to coarse	muscovite, garnet (biotite/amphibole); schistose	Garnet Schist
37	7	med to coarse	kspar, quartz, amphibole, biotite; gneissic banding or layering	Gneiss
38	11	fine to med (coarse)	quartz; non-foliated	Quartzite
39	12	med to coarse	calcite; non-foliated	Marble
40
41	SEDIMENTARY ROCKS
42	#	Grain Size	Mineral Grains / Composition	Rock Name
43	1	fine to very coarse	rock fragments (quartzite), quartz, trace others	Conglomerate
44	2	med	quartz	Quartz Sandstone
45	3	very fine (not visible)	carbon	Coal
46	4	med to coarse	qartz, kspar, (dark minerals)	Sandstone - Arkose
47	6	fine to med, coarse	calcite	Crystalline Limestone
48	10	fine to coarse	calcite, fossils	Fossiliferous Limestone
49	12	very fine	calcite	Chalk (Limestone)
50	14	very fine to fine	calcite, clay, (silt) (trace fossils)	Shale
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