You searched for: “diamond”
diamond (s) (noun), diamonds (pl)
The ultimate gemstone, having few weaknesses and many strengths: It is well known that diamonds are the hardest substances found in nature, but few people realize that diamonds are four times harder than the next hardest natural mineral, corundum (sapphire and ruby).

Diamonds are usually utilized as gemstones and an abrasives, as well as in scientific uses.

This entry is located in the following unit: Geology or Related Geological Terms + (page 5)
Gemstones or Precious and Semi-Precious Stones +
(the four gemstones which are most valuable are diamonds, sapphires, rubies, and emeralds; and anyone would be impressed with a gift of a diamond, a sapphire, an emerald, or a ruby piece of jewelry)
Word Entries containing the term: “diamond”
diamond dust
Very small, airborne ice crystals that reflect sunlight, often creating pillars of light.
This entry is located in the following unit: Meteorology or Weather Terms + (page 3)
diamond-ring effect (s) (noun), diamond-ring effects (pl)
A phenomenon seen as a flash of sunlight shineing down a lunar valley during a total solar eclipse: A diamond-ring effect is created as the total phase of a solar eclipse is about to begin, when the last Baily's bead, a remaining bit of phosphere, glows so intensely by contrast with the Sun's faint corona that it looks like the jewel on a ring.

The diamond-ring effect also refers to the equivalent phase at the end of totality.

This entry is located in the following unit: Astronomy and related astronomical terms (page 8)
diamonds, a diamond
These are the hardest and most lustrous gems because they retain their brilliance and polish for many generations.

They are a form of carbon that has been crystallized under great pressure and very high temperatures.

The two major sources for diamonds are South Africa and Australia.

"In 1695, two scientists obtained a diamond from a rich patron and heated it by using a lens to focus light on it. The diamond disappeared. Diamond is made of carbon, and it burns just as coal will when it is heated strongly enough."
—Isaac Asimov's Book of Facts by Isaac Asimov;
Bell Publishing Company; New York; 1981; page 424.
This entry is located in the following unit: Gemstones or Precious and Semi-Precious Stones + (page 1)