COLORED STONES QUESTIONAIRE #4

Which element does chromium substitute for to cause ruby's red?

Aluminum In ruby, chromium is the trace element that substitutes for aluminum in the gem's crystal structure to give the gem its red color.

The process where electrons that selectively absorb light are passed back and forth between neighboring impurity ions is known as

Charge transfer occurs when electrons that selectively absorb light are passed back and forth between neighboring impurity ions.

Which element causes the finest reds and greens in gemstones?

Chromium causes the top red colors and the best greens in gemstones, including ruby and emerald.

A gem colored by an element that is part of its basic chemistry is called

idiochromatic. An idiochromatic gem is colored by an element that is part of the gem's essential chemistry.

In many blue sapphires, the intervalence charge transfer that causes the color is between

iron and titanium. The intervalence charge transfer between iron and titanium causes the color in many blue sapphires.

What is the only type of gem that can show pleochroism?

Doubly refractive Only doubly refractive gems can show pleochroism.

Which components of a transition element's atoms can produce color in gems?

Electrons are the components of a transition element's atoms that produce color in gems.

Which transition element causes a greater variety of gem colors than any other?

Iron causes a wide variety of colors in gems.

Which element causes the color of both almandine and peridot?

Iron is the element that causes the red in almandine and the yellowish green in peridot.

Which phenomenon is a broad color flash?

Labradorescence. A broad color flash is the characteristic appearance of labradorescence.

The pattern of dark vertical lines or bands shown by certain gems when viewed through a spectroscope is called

absorption spectrum. The spectroscope can show a characteristic pattern of dark lines and bands known as an absorption spectrum.

Which gem can show three pleochroic colors?

andalusite, kyanite, tanzanite, and iolite, can show up to three, although only two colors will be visible from any one direction.

The best-known and most valuable chatoyant gem is cat's-eye

chrysoberyl. The best-known and most valuable chatoyant gem is cat's-eye chrysoberyl.

When a gem's crystal structure splits light into two rays that each travel at a slightly different speed and direction, it's called

double refraction. Most colored stones are doubly refractive, and their crystal structure splits light into two rays that each travel at a slightly different speed and direction.

Adularescence is caused by

scattering of light. Light scattered by the internal structure of moonstone causes its adularescence.