<p>This isn't a rock at all, but a seed of <em><a href="https://en.m.wikipedia.org/wiki/Entada_gigas" rel="nofollow noreferrer">Entada Gigas</a></em>, sometimes called the <strong>sea heart</strong> or <strong>sea bean</strong>. </p>

<p><img src="https://upload.wikimedia.org/wikipedia/commons/b/b7/Entada_gigas1.jpg" alt="Entada Gigas seeds">
(<a href="https://commons.wikimedia.org/wiki/File:Entada_gigas1.jpg#mw-jump-to-license" rel="nofollow noreferrer">CC-BY-SA-3.0</a>)</p>

<p><em>Entada Gigas</em> is called the "sea bean" for good reason: it's a member of the bean family <em><a href="https://en.m.wikipedia.org/wiki/Fabaceae" rel="nofollow noreferrer">Fabaceae</a></em>. In fact, this species has the family's largest seed,  a flattened heart shape 6 cm in diameter and 2 cm thick.  These hollow seeds are washed into the ocean and drift on currents for up to 2 years, on the chance that one will wash up somewhere to germinate.  It seems that sea beans have evolved to propagate in this way, similar to <a href="https://en.m.wikipedia.org/wiki/Coconut" rel="nofollow noreferrer">coconut</a>s.</p>

CC BY-SA 4.0
2018-08-05T16:28:05.850Z
2018-08-06T10:56:50.283Z
2018-08-06T10:56:50.283Z
Spencer
<p>I found the rock on the beach.  It has a redish hue and floats on water.  It feels as though it is hollow because it is light for its size.  Does anyone have an idea what this is?<a href="https://i.sstatic.net/PixBf.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/PixBf.jpg" alt="enter image description here"></a></p>

CC BY-SA 4.0
2018-08-05T14:47:55.910Z
you sure its not plastic?
John
CC BY-SA 4.0
2018-08-06T10:30:58.667Z
Rocks usually do not float on water. The only rocks that float on water are very porous rocks like [pumice](https://en.wikipedia.org/wiki/Pumice).
Gimelist
<ocean>
Floating rock found in southern florida
user13554
# Floating rock found in southern florida

(Asked by: username_0 on 2018-08-05)

I found the rock on the beach. It has a redish hue and floats on water. It feels as though it is hollow because it is light for its size. Does anyone have an idea what this is?[![enter image description here](https://i.sstatic.net/PixBf.jpg)](https://i.sstatic.net/PixBf.jpg)

**Tags:** ocean

> **Comments:**
> **username_1**: you sure its not plastic?  
> **username_2**: Rocks usually do not float on water. The only rocks that float on water are very porous rocks like [pumice](https://en.wikipedia.org/wiki/Pumice).  

---

## 1 answers

### Answer by username_3 on 2018-08-05. Score: 10

This isn't a rock at all, but a seed of *[Entada Gigas](https://en.m.wikipedia.org/wiki/Entada_gigas)*, sometimes called the **sea heart** or **sea bean**.

![Entada Gigas seeds](https://upload.wikimedia.org/wikipedia/commons/b/b7/Entada_gigas1.jpg)
([CC-BY-SA-3.0](https://commons.wikimedia.org/wiki/File:Entada_gigas1.jpg#mw-jump-to-license))

*Entada Gigas* is called the "sea bean" for good reason: it's a member of the bean family *[Fabaceae](https://en.m.wikipedia.org/wiki/Fabaceae)*. In fact, this species has the family's largest seed, a flattened heart shape 6 cm in diameter and 2 cm thick. These hollow seeds are washed into the ocean and drift on currents for up to 2 years, on the chance that one will wash up somewhere to germinate. It seems that sea beans have evolved to propagate in this way, similar to [coconut](https://en.m.wikipedia.org/wiki/Coconut)s.


---

