Amazonite

Apatite

Aragonite

Calcite

Celestite

Feldspar

Fluorite

Fossils

Amber

Jet

Stromatolite

Glass

Obsidian

Hemitite

Howlite

Kyanite

Quartz

Attributes
Crystal System: Hexagonal
Composition: Silicone and Oxygen (SiO2)
Crystal habit: 6-sided prism ending in 6-sided pyramid (typical), drusy, fine-grained to microcrystalline, massive
Mohs hardness: 7
Luster: Vitreous – waxy to dull when massive
Diaphaneity: Transparent to opaque
Solubility: Insoluble

Grows in "twinned" pairs in opposite slanted directions, causing a bed of quartz to be a knot work of crystals. Large flawless specimens are artificially grown.

Macrocrystalline

Diaphaneity: Transparent

Clear Quartz Crystal

Also known: Rock crystal
Color: Colorless

Rutilated Quartz

Contains needle-like inclusions of rutile

Herkimer Diamond

Color: Colorless

Citrine

Physical Attributes
Color: Yellow to reddish orange or brown. Occasionally greenish yellow.
Location: Primarily Brazil
Commercially sold citrine is usually heat treated amethyst.

Metaphysical Attributes
Also known as "merchant's stone" or "money stone" because it brings prosperity.[5]

Amethyst

Color: Purple to violet
Location: Brazil, Mexico, Uruguay, Russia, France, Namibia and Morocco

Ametrine

Color: Mixed amethyst and citrine hues
Amethyst and citrine are often found on the same bed and can blend together into ametrine.

Rose Quartz

Color: Pink
May display diasterism from microscopic rutile.
Color comes from trace amounts of titanium, iron, or manganese.

Smoky Quartz

Color: Shades of gray, sometimes brown or black
Diaphaneity: Transparent to opaque

Microcrystalline

Aventurine

Tiny inclusions (usually mica) creating aventurescence
Diaphaneity: Translucent to opaque

Cryptocrystalline

Fibrous
Diaphaneity: Translucent to opaque

Chalcedony

Color: Various. White and light colors are simply classified as "chalcedony" while other colors are given specific names.

Carnelian

Color: Reddish orange
Widely heat treated to deepen color.

Dumortierite quartz

Color: Blue, sometimes purple or gray
Contrasting dark and light zones

Milky Quartz

Color: White
May have diasterism. Contains minute fluid inclusions of gas, liquid, or both, trapped during crystal formation. [6]

Prasiolite

Also known: Vermarine
Color: Mint or olive green
Location: Brazil, Poland, Canada
Rare. Commercially sold green quartz is usually heat treated amethyst.

Tiger's Eye

Color: Fibrous gold, red-brown, or bluish
Exhibits chatoyancy

Agate

Color: Bands of various color
Diaphaneity: At least one band is translucent

Onyx

Color: Straight bands of color

Jasper

Color: Various
Diaphaneity: Opaque

Ruby

Selenite

Shungite

Stone

It is incredibly difficult to classify the relationships between the different types of quartz, especially when scientific and colloquial definitions are at odds.

Chalcedony and cryptocrystalline refer to the same quartz qualities, but here I separate the terms leaving chalcedony to only refer to single colored cryptocrystalline rocks.
Microcrystalline is an umbrella term that includes cryptocrystalline, but here I separate it to mean translucent rocks with notable inclusions.

I've defined the general quartz taxonomy as this:

  • Macrocrystalline: Transparent
  • Microcrystalline: Translucent or opaque with notable inclusions
  • Cryptocrystalline: Translucent or opaque
    • Chalcedony: Single color translucent
    • Agate: Banded colors, at least one translucent
    • Jasper: Opaque
Bibliography
1. Quartz Archived 14 December 2005 at the Wayback Machine. Mindat.org. Retrieved 2013-03-07.
2. Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (eds.). "Quartz" (PDF). Handbook of Mineralogy. III (Halides, Hydroxides, Oxides). Chantilly, VA: Mineralogical Society of America. ISBN 0962209724.
3. Quartz Archived 12 November 2006 at the Wayback Machine. Webmineral.com. Retrieved 2013-03-07.
4. Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20 ed.). ISBN 0-471-80580-7.
5. The Encyclopedia of Superstitions By Richard Webster, p. 19
6. Hurrell, Karen; Johnson, Mary L. (2016). Gemstones: A Complete Color Reference for Precious and Semiprecious Stones of the World. Book Sales. p. 97. ISBN 978-0-7858-3498-4.