Why does the sand on Coronado Beach sparkle?
It's mica, a flaky natural mineral that catches the light like gold glitter. It isn't gold, and it isn't pollution — it's part of why Coronado's Central Beach is famously bright.
- The sparkle
- Mica
- Dr. Beach rank
- No. 1
- Best light
- Golden hour
Not gold, not glitter, not pollution
2012
Low sun makes it flash
The short version
- The gold flecks are mica, a common mineral that splits into thin, shiny flakes — Coronado's tourism bureau says so directly.
- Coronado was ranked America's No. 1 beach in 2012 by Stephen Leatherman, the coastal scientist known as Dr. Beach.
- It climbed to that spot from No. 3 in 2010 and No. 2 in 2011.
- Dr. Beach cited a flat, hundreds-of-yards-wide beach, excellent water quality and strong lifeguarding.
- The sparkle is most visible in low, slanting light — early morning and the hour before sunset.
Walk Coronado's Central Beach near sunset and the wet sand looks dusted with gold. First-time visitors regularly ask whether it's real gold or something washed in. It's neither: it's mica, a common mineral that cleaves into paper-thin flakes with flat, mirror-like faces.
No. 3
Dr. Beach, 2010
No. 2
Dr. Beach, 2011
No. 1
Dr. Beach, 2012
Why mica flashes
Most sand grains are rounded, so they scatter light in every direction. Mica flakes are flat. When the sun is low, thousands of tiny flat faces line up at the right angle and bounce light straight at you, which is why the effect comes and goes as you walk and almost disappears at noon.
Is it gold?
| Mica | Gold | |
|---|---|---|
| Shape | Thin, flat flakes | Grains or nuggets |
| Weight | Light — washes around with the sand | Very heavy — sinks out of moving sand |
| When it shines | Flashes in low sun, vanishes at other angles | Shines from any angle |
| On Coronado Beach | Everywhere | No |
Is it really the best beach in America?
In 2012 Stephen Leatherman — the Florida International University coastal scientist who publishes an annual ranking as Dr. Beach — put Coronado at No. 1, after No. 3 in 2010 and No. 2 in 2011. He pointed to a beach that is flat and hundreds of yards wide, a mild Mediterranean climate, excellent water quality and a strong lifeguard program.
- Go at golden hour if you want the sparkle in photos.
- Wet sand at the waterline shows it best.
- Mica is harmless; it washes off like any other sand.
KEEP READING
SOURCES
Everything above traces back to one of these. Follow them — if one has changed and we haven't, that's our mistake, not yours.
Discover Coronado (Coronado tourism) · 2024
States that the gold specks are mica, not gold
NBC News · May 2012
Coronado ranked No. 1, up from No. 2 (2011) and No. 3 (2010); Leatherman's reasons