UMass Amherst Professor Stephen Haggerty Speaks on Origins of Black Diamonds

June 2, 1997


AMHERST, Mass. - Professor Stephen E. Haggerty of the University of Massachusetts department of geosciences delivered the fifth annual Daly Lecture at the spring meeting of the American Geophysical Union in Baltimore on May 27.

He spoke on "Diamonds and High Pressure Rocks: Clues to the Geodynamics of the Earth''s Interior." Haggerty has long been interested in the origin of diamond and the clues the stone can offer about the earth''s interior, and is a leading expert on the subject. Diamond is formed 100 to 300 miles below the earth''s surface under intense heat and pressure, before being pushed to the planet''s surface.

Haggerty''s studies have recently focused on South American carbonadoes, large black diamonds composed of dense aggregations of smaller crystals. He has hypothesized that carbonado, which has a different mineralogy than regular, earth-formed diamonds, may have been created in outer space, as part of dying stars, fragments of which later fell to earth. Carbonado''s color is due to its porous structure, and common inclusions of other minerals. The clear diamonds that are cut into gemstones are single crystals.

Haggerty''s work has taken him to five continents, particularly Africa, Asia, and Australia. His study of minerals occurring with and in diamond has illuminated both the search for diamond and the site of its formation. He was the first to describe high-pressure minerals that may have come from the transition zone of the earth''s mantle, more than 250 miles deep.

Haggerty holds the Chancellor''s Medal from the University of Massachusetts as a distinguished faculty lecturer. He was recently honored by the name haggertyite, a newly discovered mineral composed mainly of barium, titanium, and silica. He has taught at the University since 1971.

The Daly Lecture was established to honor professor Reginald A. Daly of Harvard University, who was among the foremost scholars of the depths of the earth in the early twentieth century. Among his theories was the now-accepted hypothesis that the moon was created by a planetary impact on the earth early in the history of the solar system.