10 Questions
What is the common characteristic of feldspar, spodumene, and diopside?
They have cleavage in two directions
What is the term for the vivid blue adularescence displayed by the finest moonstone?
Blue sheen
What is the origin of the color in kunzite?
Irradiation and heating
What is the most common cutting style for moonstone?
Cabochon
What is the cause of labradorite’s phenomenal colors?
Interference of light reflecting off the gem’s layered structure
What is the characteristic of sunstone that gives it a reddish or golden sheen?
Small inclusions
What is a characteristic of chrome diopside?
It has high clarity and is not treated
What is the term for an imitation of aventurine feldspar?
Goldstone
What is the characteristic of moonstone that makes it rare and expensive?
Fine quality
What is the common characteristic of feldspars?
They are the most widespread minerals on earth
Study Notes
Feldspar, Spodumene, and Diopside
- Feldspar, spodumene, and diopside are soft gems with cleavage in two directions, requiring protective settings.
- Feldspars are the most widespread minerals on earth.
- Moonstone, a type of feldspar, exhibits adularescence due to the scattering of light by stacked, alternating mineral layers.
Moonstone
- The finest moonstones have a colorless, semitransparent to nearly transparent appearance and vivid blue adularescence.
- Moonstones are readily available in modestly priced, calibrated sizes, but rare and expensive in fine quality.
- The most common cutting style for moonstone is the cabochon.
Labradorite
- Labradorite's phenomenal colors are caused by interference of light reflecting off the gem's layered structure.
- The most prized labradorite type is "spectrolite," a phenomenal labradorite with brilliant spectral hues.
Spodumene
- Kunzite, a type of spodumene, is most commonly light pink, but its most valuable colors are intense pink and intense violetish purple.
- Light-colored or colorless spodumene is irradiated and then carefully heated to produce kunzite's rosy color, but the color can fade under heat or bright light.
Diopside
- Chrome diopside is an effective emerald alternative due to its high clarity and lack of treatment.
Key Terms
- Blue sheen: Trade term for a highly prized, vivid blue adularescence displayed by the finest moonstone.
- Goldstone: An imitation of aventurine feldspar made of glass containing small copper crystals.
Explore the characteristics of soft gems like feldspar, spodumene, and diopside, including their cleavage and optical properties. Learn about the prized 'spectrolite' labradorite and the effects of inclusions on sunstone.
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