Q 01/05

Traces of chromium turn clear crystals of aluminum oxide into which precious gemstone?

A) Amethyst

B) Ruby

C) Topaz

D) Opal

Answer · why

B) Ruby

Ruby owes its red to chromium atoms that take the place of about one in a hundred aluminum atoms. The same crystal without chromium is called sapphire...

Q 02/05

Trace amounts of chromium give which gemstone, a variety of the mineral beryl, its famous green?

A) Peridot

B) Malachite

C) Turquoise

D) Emerald

Answer · why

D) Emerald

Emerald is beryl tinted by chromium or sometimes vanadium, so the metal that makes one famous gem red makes another green.

Q 03/05

Chrome yellow, a chromium pigment, was chosen in 1939 as the paint for which North American vehicles?

A) School buses

B) Taxi cabs

C) Fire engines

D) Mail trucks

Answer · why

A) School buses

School buses wore a shade first officially named National School Bus Chrome. Its lead chromate pigment was later replaced because it is toxic.

Q 04/05

Which 2000 film stars Julia Roberts exposing chromium-poisoned groundwater in Hinkley, California?

A) The China Syndrome

B) A Civil Action

C) Erin Brockovich

D) Dark Waters

Answer · why

C) Erin Brockovich

Erin Brockovich tells the true story of a case settled for $333 million in 1996, and it won Julia Roberts the Academy Award for Best Actress.

Q 05/05

Chromium on 2,200-year-old bronze weapons at which Chinese site was long mistaken for an ancient protective coating?

A) Forbidden City

B) Terracotta Army

C) Mogao Caves

D) Great Wall of China

Answer · why

B) Terracotta Army

Terracotta Army weapons were thought to have been chromium-coated to stop decay, until research in 2019 showed the metal was contamination from nearby...