THE JGRL GEM LIBRARY
Get to know gemstones.
Discover the reasons for their beauty.
The structure behind a color. The place a gem formed. The cut that brings out its light.
A collection of fundamentals to help you understand each stone.
Crystals / Origins / Colors / Hardness / Cuts
EXPLORE THE GEMSTONES
Explore gemstones
Search by name or color to discover a gemstone.
Diamond
Diamond
A gemstone composed of carbon, known for high hardness and the reflection and dispersion of light through its polished facets.
- Mohs hardness
- 10
- Crystal system
- Cubic (isometric)
Spinel
Spinel
A distinct mineral whose red stones were sometimes confused with ruby in history. Blue, gray and many other colors are also found.
- Mohs hardness
- 8
- Crystal system
- Cubic (isometric)
Alexandrite
Alexandrite
Chrysoberyl whose apparent color changes with the light source. The strength of the change differs between stones.
- Mohs hardness
- 8.5
- Crystal system
- Orthorhombic
Chrysoberyl Cat’s-eye
Chrysoberyl Cat’s-eye
Chrysoberyl displaying a single luminous band. The term cat's-eye also describes an optical effect seen in other materials.
- Mohs hardness
- 8.5
- Crystal system
- Orthorhombic
Garnet
Garnet
A gemstone group extending far beyond red, including green tsavorite and demantoid.
- Mohs hardness
- 6.5–7.5
- Crystal system
- Cubic (isometric)
Peridot
Peridot
A yellow-green gem whose color relates to iron in its mineral composition, with a characteristic fresh olive hue.
- Mohs hardness
- 6.5–7
- Crystal system
- Orthorhombic
Topaz
Topaz
A gem available in blue, pink, colorless and other colors, extending well beyond the yellow traditionally associated with its name.
- Mohs hardness
- 8
- Crystal system
- Orthorhombic
Tourmaline
Tourmaline
A mineral group with a rich color range. Some individual crystals display several colors together.
- Mohs hardness
- 7–7.5
- Crystal system
- Trigonal
Tanzanite
Tanzanite
The blue-to-violet variety of zoisite, commercially sourced from the Merelani area in northern Tanzania.
- Mohs hardness
- 6–7
- Crystal system
- Orthorhombic
Jadeite Jade
Jadeite Jade
Jade can be white or lavender as well as green. Jadeite jade and nephrite jade are distinct materials.
- Mohs hardness
- 6.5–7
- Crystal system
- Monoclinic
Zircon
Zircon
A natural mineral capable of strong brilliance. It is a different material from manufactured cubic zirconia (CZ).
- Mohs hardness
- 6–7.5
- Crystal system
- Tetragonal
Illustrations suggest color and shape. Individual stones vary; each gem page includes further details and references.
A LITTLE KNOWLEDGE, A DEEPER APPRECIATION
The more you know,
the more there is to discover.
How do hardness and toughness differ?
Understand the language of gems, one idea at a time.