What Is the Grass Carp Stone? A Detailed Guide to Removal, Polishing, Care and Price

You are probably quite familiar with the grass carp, but you may never have heard that a grass carp stone is hidden in its head. So what is the grass carp stone? How do you remove it? How do you polish and care for it?

The grass carp stone, also known as the black carp stone, fish scare stone, fish essence stone and fish pillow stone, is a keratinous growth located below the occipital bone in the throat area of the grass carp, used to help crush hard foods such as snails. It is tender yellow in color and heart-shaped, and once thoroughly dried it becomes as hard as stone, crystal clear, like jade or emerald, and is treasured as a rare item in Hakka regions. It can be strung on a cord and worn around a child's wrist, and is said to ward off evil and misfortune, prevent children from being frightened, and bring good fortune and prosperity, hence the name grass carp stone.

A finely crafted grass carp stone has a texture like angel skin coral, a color comparable to Saiga antelope horn, and a clarity like amber or beeswax, making it a delight to hold. The grass carp (black carp) that produces this stone, also known as the snail-eating carp, belongs to the genus Mylopharyngodon in the family Cyprinidae, is a freshwater fish, and can weigh up to several tens of kilograms. This fish likes to eat hard snails, and the grass carp stone is a keratinous pad in the throat area below the occipital bone, used to help crush snails, formed through evolution over many years. Other ordinary fish do not have this stone, which is why it is considered rare and precious. After the grass carp stone is removed and naturally dried, its material becomes stable and can be preserved for a long time. Raw grass carp stones cost about 10 yuan each on Taobao, with weights between 54.3 and 4.8 grams. Finished products vary in price depending on the craftsmanship, ranging from a few dozen to over a hundred yuan.

Since the grass carp stone is so remarkable, how do you obtain one? Below is a detailed account of a netizen's process for harvesting a grass carp stone:

How do you remove the grass carp stone?

The grass carp stone is located on the occipital bone above the teeth in the throat area of the grass carp. Upon inspecting this area, you can clearly see a heart-shaped foreign object set in a ring on the upper palate but relatively independent and not connected to the other fish bones. Generally, its obvious difference from the other bones is visible to the naked eye, and once found, you should try to remove it.

Stone removal process:

1. Prepare your tools, a pair of scissors and a spoon, and cut off the grass carp head along the large joint of the pectoral fin.

2. Use the scissors to cut open the large joint of the grass carp pectoral fin; using scissors ensures you do not damage the grass carp stone.

3. Pry open the cut large joint of the pectoral fin, and you will then be able to see the grass carp stone on the upper part of the fish occipital bone.

4. Use the spoon to pry the grass carp stone off the fish occipital bone. This is actually the most critical step; a fresh grass carp stone is relatively soft, and improper prying can easily damage it, causing cracks and scratches, so finding the right tool is crucial.

5. The curvature of a stainless steel spoon fits the curvature of the grass carp stone perfectly, allowing you to pry it off very skillfully without damaging it, far more suitable than using a knife, scissors or similar tools.

How do you store the grass carp stone?

The grass carp is an aquatic organism, and a fresh grass carp stone contains a large amount of water. After removal, it must be left to dry in the shade until it solidifies into a hard keratinous substance before it can be worked.

Never dry the grass carp stone by sun-drying, air-blowing or oven-drying. These rapid dehydration methods will cause the grass carp stone's moisture level to change drastically in a short time, producing numerous cracks.

Therefore, a freshly harvested grass carp stone should be stored in a cool, windless, dark and dry environment for more than half a month, to let it dry naturally in the shade.

After drying, the grass carp stone is orange with a pink tint and has an attractive color. If the raw material needs oiling for care, you should wait until the grass carp stone is thoroughly dry before applying oil; oiling too early will affect the evaporation of moisture from the stone and interfere with subsequent processing and polishing.

How do you polish the grass carp stone?

The grass carp is an aquatic organism, and a fresh grass carp stone contains a large amount of water. After removal, it must be left to dry in the shade until it solidifies into a hard keratinous substance before it can be worked.

1. Preliminary cleaning

The grass carp stone has two sides, one a growth surface and one a chewing surface. The chewing surface is usually severely worn and aged, and sometimes even retains snail shells embedded when the grass carp was chewing. Before polishing the grass carp stone, the aged portion of the chewing surface must be cleaned off.

In addition, the aged portion of the grass carp stone has a strong fishy odor, and cleaning it before polishing can reduce the fishy smell during the polishing process.

2. Gluing to "protect the work."

This gluing process, which prevents cracking and chipping during polishing, is called "protecting the work" in trade jargon, and is more applicable to grinding with a bench grinder or engraving machine, mainly to prevent chipping during the polishing process.

However, the grass carp stone has a certain toughness and is not very prone to chipping, so this step can be omitted for hand polishing, but you must pay attention to the problem of friction-generated heat during polishing. The chewing surface of the grass carp stone is usually severely aged and covered with cracks; after gluing, the glue penetrates into the cracks and can play a good role in preventing cracking.

In addition, many friends like to use the method of soaking in oil to maintain and preserve raw grass carp stones. But in fact, soaking in oil is of no benefit to unprocessed grass carp stones; after soaking, the surface cracks of the stone are filled with oil and become difficult to distinguish.

Often, during processing it looks as if there are no cracks left, but after final polishing and drying, the cracks reappear. This then requires polishing again, wasting time and effort. It is more appropriate to apply oil for care after processing is complete.

3. Shaping and rough grinding

Here we use sandpaper as the polishing tool.

In the first step, you can use 180-grit to 400-grit sandpaper to remove impurities and cracks from the surface of the grass carp stone and to grind its shape into a regular form. During polishing, pay attention to the problem of friction-generated heat; excessive friction heat may cause new fine cracks in the grass carp stone.

If you choose to use water sandpaper for grinding, never soak the grass carp stone in water. The grass carp stone has a certain water absorption capacity, and after absorbing water and swelling, it is prone to cracking during processing. Therefore, it is best to grind with a small amount of water dipped on the surface, and wipe it dry immediately after grinding.

4. Fine shaping and detailed grinding

This step requires finely grinding the grass carp stone after rough grinding and shaping. Coarser 180-400 grit sandpaper will leave scratches on the surface of the grass carp stone, so a stone that has only been rough-ground cannot be directly polished.

Therefore, you need to use 800-grit, 1000-grit, 3000-grit and 5000-grit sandpaper for transitional grinding, to smooth out surface scratches as much as possible. During polishing, you must also pay attention to the problem of friction-generated heat.

What needs attention here is the control of water and humidity during polishing. The basic technique is that as the sandpaper becomes finer, the amount of water dipped should gradually decrease, and at 5000 grit and above, you can grind dry.

5. Fine polishing

A finely polished grass carp stone will present a jelly-like texture, with a tender pink color and a luster like jade.

How do you give the grass carp stone a mirror polish?

Method 1: After shaping and polishing the grass carp stone to 5000 grit, let it dry naturally in the shade for 1-2 days, then use 7000-grit sandpaper for dry grinding and polishing.

Method 2: After shaping and polishing the grass carp stone to 5000 grit, let it dry naturally in the shade for 1-2 days, then use a cotton cloth dipped in toothpaste to wipe directly on the surface of the grass carp stone until a mirror effect appears. Finally, quickly wash off the toothpaste and let it dry naturally in the shade.

How do you care for the grass carp stone?

The main component of the grass carp stone is keratin protein; it is warm and smooth in texture and attractive in color. When wearing it normally, pay attention to changes in humidity, protect it from wind, sun and rain, and strictly avoid direct blowing from air conditioning or heating. It fears water and likes oil; otherwise, the surface is prone to cracking.

It can be stored in a sealed bag or jewelry box, with a little oil applied for care. It is recommended to use mineral oils such as Vaseline or baby oil; do not use cooking oil, as cooking oils tend to mold and breed bacteria.

In addition, the hardness of the grass carp stone is around 3 on the Mohs scale. A thoroughly dried grass carp stone is difficult to scratch with a fingernail and has toughness. Never scrape it against hard objects such as metal, otherwise it will easily develop scratches.

Organic collectibles such as ivory and horn usually develop an aging phenomenon, the so-called patina, mainly caused by oxidation and changes in humidity, generally taking from a few years to several decades, depending on the specific storage conditions.

After aging and developing a patina, the grass carp stone has an effect like the crackle pattern of old amber, with a dragonfly-wing pattern, also rich in beauty.

Reference table matching grass carp stone to grass carp size and weight

The weight of a grass carp stone is determined by its size and thickness; grass carp stones of the same size may differ greatly in weight due to differences in thickness;

The grass carp stone depends on the fish's age, the fish's body size and the completeness of the stone; grass carp stones produced by fish of the same size may differ greatly in size.

Uses

Many places in the south often have the custom of curing dried grass carp. During the curing process, one tries to remove the fish stone one to two weeks after salting; the fish stone will have a more aged and antique color, with the internal crackle pattern shown in the illustration. With the salty taste absorbed inside, when a child is frightened or startled, letting them actively suck on it, or when an adult feels frightened, holding it under the tongue, can often immediately stop the unpleasant feeling. According to analysis, what may be at work is still psychological factors.