Query: Was a gold ball really thrown out to start season?

[Gerald Cohen]

   This isn't from the 19th century, but maybe someone could help. The
newspaper _San Francisco Bulletin_ (April 2, 1913)  mentions a gold
ball being thrown out to open  the baseball season of the Pacific
Coast League.

     What exactly is meant by a gold ball? It's not likely to have
been solid gold.
Was it just gilded a bit on the surface? There was a type of ball
called a Goldsmith, but that didn't seem to be anything special.

   So I guess the question comes down to: How much gold was there in
the gold ball that was thrown out to open the season?  Would anyone
be familiar with this custom (throwing out a gold ball)?

    Any help would be much appreciated. The relevant quote appears
right after my signoff.

Gerald Cohen

_San Francisco Bulletin_, April 2, 1913, p.17/3-5; 'Thirteen
Combination Upsets Seals'; col. 5: 'Mayor Rolph was on the job with
the first ball. "Doc" Frost, with chest expanded and his chin high in
the air walked out to the mound and presented the city's Chief
Executive with a gold ball, which his Honor promptly sent hurtling
toward the plate.  His arm was not in good shape, however, and the
gold ball crossed the batting station still a ball.  Which goes to
show that a ball is not a ball when it is a strike! But, again, the
gold ball was a ball, however, consequently and nevertheless.'