Yes, some sponges are natural, but they are not a plant as most people think. They are an animal, albeit a very simple one. I came across a soap website that had everything I was checking for; totally natural soap and honesty. He also had a paragraph where he attested to no animal testing, all natural ingredients, eco-friendly products. Everything was correct except for his sea sponges. He stated they were from a sustainable farm, with fair trade applications, and not harvested from the wild, which is all good so far. Unfortunately, he did not realize that they were animals. You can not be against animal testing then sell dead ones. But I realize that most people do not know this, or had forgot this.
A sea sponge has no mouth, no muscles, no nervous system, no heart and no brain. But they can change the shape of their bodies, move specific cells from one location to another location and have those cells change their purpose. (creating great interest in medical research). Some varieties of sponge can also move, very slowly, 1 - 4 mm per day, they eat, and reproduce with sperm and ova as well as reproducing asexual (without sperm/ova).

Their scientific name is Porifera, meaning animals that have pores. There are more than 15,000 varieties, and they live primarily in the ocean, some near the edge, some in deep water, some in fresh water. They all filter little bits of food from the water that passes through them. Their use almost lead to their extinction, until synthetic versions were manufactured. Luffas or loofah, are of plant origin, these are the fibrous insides of cucurbitaceae gourds.

There are 3 different types of these simple animals. These differences are in regarding to how their skeleton is made. Demosponges if the main category, creating their skeleton from spongin which is a protein. Bony varieties, also known as Calcarea, use calcium carbonate, and they comprise about 3% of known species. At 7% of known varieties, is the Glass, or Hexactinellida, that uses silicon dioxide. This type usually lives in the deeper areas of the ocean.

There are a few species that, in the event of little available food, will eat crustaceans. Generally these types live deep in the ocean.

Synthetic sponges, and natural ones, are used as tools and cleaning aids. Great for absorbing water solutions. Commonly, the synthetics are made from cellulose wood fibers or foamy plastic polymers. Nowadays, the natural ones tend to be used for bathing, painting techniques and make up applicators.

The three categories for the synthetic varieties are the low-density polyether, PVA, and polyester. One of the biggest negatives regarding synthetic varieties is the harboring of harmful bacteria and fungi, which occurs when left damp between uses. Some manufacturers treat this type with anti-microbials, which carries it's own set of concerns. To kill the bacteria, soak it in clean water for one minute, then microwave on high for two minutes. Make sure it is wet or it may catch fire during microwaving.

Author's Bio: 

Courtney Findlay is a professional soapmaker that creates natural soap and bath products and promotes healthy information and soap knowledge at