Copyright © Shiraishi Group ALL RIGHTS RESERVED.
Copyright © Shiraishi Group ALL RIGHTS RESERVED.
The World of Calcium
October, 3rd 2025
Table of Contents
Japan’s mountains, cliffs, and karst landscapes hide a fascinating story of ancient seas and plate tectonics. Limestone, the main source of calcium carbonate, is found across the Japanese archipelago – from Hokkaido in the north to Okinawa in the south. But how did it get there, and what makes it unique?
Much of Japan’s limestone originated from coral reefs and other marine deposits near the equator in the central Pacific. Over millions of years:
Image © Limestone Association of Japan – reproduced with permission.
While the main component is calcium carbonate (CaCO₃), natural limestone usually contains small amounts of:
These trace elements vary depending on the organisms that originally formed the limestone and the surrounding environment.
Crystal Structures:
Fun fact: High-purity crystalline limestone is used to make heavy calcium carbonate, while thermal or chemical processes can produce light or colloidal calcium carbonate.
Japan’s limestone is not only geologically fascinating but also economically important. Mines across the country supply raw material for:
These modern uses all trace back to ancient seas and fossilized marine life.
The limestone under Japan’s mountains tells a story spanning hundreds of millions of years – from coral reefs near the equator to active mines today. Understanding its origins gives us a deeper appreciation for the mineral that plays a key role in both our industries and our health.
December, 4th 2025
Calcium in the Human Body – Importance and Utilization
Introduction Calcium is much more than a mineral in your diet – it’s a critical building block for life. About 1.5–2% of the human body is calcium, most of which resides in bones and teeth as calcium phosphate. The rest circulates in blood and extracellular fluids, performing vital functions. The Role of Calcium in the Body Calcium is essential for: Bone and tooth formation – providing strength and structure Nerve transmission – sending signals throughout the body Muscle contraction – enabling movement and heartbeats Cell membrane function – maintaining proper permeability Blood clotting – crucial for wound healing Calcium Metabolism Most dietary calcium enters the body as calcium compounds (from food or supplements) In the digestive system, calcium dissolves into ions and is absorbed in the small intestine Bone remodeling: calcium is constantly deposited and removed from bones to maintain a stable plasma calcium concentration Growth and aging: Until about 25 years old, bone formation exceeds calcium loss, increasing bone mass With age, calcium loss may exceed formation, leading to bone weakening and osteoporosis Adequate calcium intake during growth is key to maximizing bone mass As shown on the map, there is currently a deficiency in calcium intake in many Asian countries (red/orange). In contrast, countries with higher consumption of dairy products often achieve adequate calcium intake (green). Source：Pub Med Central - Global dietary calcium intake among adults: a systematic review Factors Affecting Calcium Absorption Calcium absorption is influenced by: Dietary components: Oxalic acid (in spinach), phytic acid, and dietary fiber can reduce absorption Life stage: Infants, pregnant women, and post-menopausal adults have different calcium needs Vitamin D levels: Essential for proper calcium absorption Studies show: Calcium absorption from vegetables depends on the presence of inhibitors like oxalates Overall absorption rates are about 20–30%, varying with age, diet, and health status Conclusion Calcium is a vital mineral that goes far beyond building bones. Its absorption and utilization are influenced by diet, lifestyle, and life stage. Ensuring adequate calcium intake, especially during growth and later life, is key to maintaining strong bones and overall health.
October, 8th 2025
Calcium Carbonate – From Rock to Daily Life
Introduction From the limestone mountains to your breakfast cereal or supplement, calcium carbonate (CaCO₃) travels a fascinating journey. But how does this mineral go from a natural rock to a substance we use every day in food, industry, and medicine? Ground vs. Precipitated Calcium Carbonate Calcium carbonate comes in two main types, depending on how it’s processed: 1. Ground Calcium Carbonate Produced by crushing and classifying crystalline limestone Known as white calcium carbonate due to its bright whiteness Particle size: can occure in a variety of sizes Uses: industrial fillers, food additives, pharmaceuticals Shiraishi Calcium Kaisha deals with GCC products as well 2. Precipitated Calcium Carbonate Made chemically by calcining limestone to quicklime, then hydrating it and reacting it with carbon dioxide Fine particles (even on a nano scale for industrial use) Uses: food, cosmetics, and high-tech industrial applications Shiraishi Kogyo Kaisha primarily produces PCC, using the carbon dioxide gas synthesis method, allowing us to precisely control particle size and shape Why Calcium Carbonate Matters Calcium is one of the most abundant elements in the Earth’s crust, but it never exists freely in nature. Instead, it is found as: Carbonates (CaCO₃) Sulfates, fluorides, phosphates, silicates Many of the calcium compounds we consume in food are derived from calcium carbonate. Even familiar sources like eggshells, bones, and shells originally obtained their calcium from limestone, either directly or through animal feed. Everyday Uses Calcium carbonate’s versatility makes it a key material in daily life: Food: supplements, fortification, antacids Industry: fillers, paper, plastics, paint Agriculture: soil conditioner, animal feed Medicine: calcium tablets and pharmaceuticals This transformation from rock to refined mineral shows how geology directly impacts our health and industries. Conclusion The next time you take a calcium supplement or see calcium listed on a product label, remember: it all starts as limestone, formed millions of years ago in ancient seas. From fossilized coral to modern industry, calcium carbonate bridges the gap between the Earth’s history and our daily lives.
October, 7th 2025
The Birth of Calcium Carbonate – A Journey Back to the Ancient Sea
Introduction Calcium is essential for life – from building strong bones to supporting blood clotting. But did you know that the calcium we consume today has its origins in the ancient oceans, millions of years ago? The story of calcium carbonate, the main component of limestone, is a fascinating journey through Earth’s deep history. From Corals and Algae to Limestone Calcium carbonate (CaCO₃) occurs naturally as limestone, marble, and chalk. But how do tiny marine organisms turn into massive rocks over time? Biological deposits: The shells and skeletons of organisms such as foraminifera, corals, and calcareous algae accumulate on the seafloor. Over millions of years, these layers compact and solidify into limestone. Inorganic processes: Calcium ions in seawater can combine with carbon dioxide to form calcium carbonate, which also settles on the ocean floor. Fun fact: Most limestone actually comes from biological sources rather than purely inorganic calcium carbonate. The Power of Time and Nature These deposits undergo geological processes like cementation, crystallization, and compaction before becoming solid rock. Cementation: minerals fill the spaces between particles, binding them together Crystallization: the mineral components form stable crystals Compaction: layers of sediment are pressed together under pressure, reducing gaps and increasing density Over millions of years, these limestone layers may rise above the Earth’s surface, forming stunning landscapes. Examples from nature: Fuxed Coral – fossils revealing ancient coral reefs Akiyoshidai Karst, Yamaguchi – striking karst formations made of amorphous limestone Image © Limestone Association of Japan – reproduced with permission. Limestone Around the World Limestone is far from rare. Carbonate rocks make up about 15–20% of all sedimentary rocks, and an estimated 5×10¹⁷ tons exist within the Earth’s crust – a massive reservoir of carbon dioxide bound over billions of years. But how much is 5×10¹⁷ tons? 500,000,000,000,000,000 tons – that’s five hundred quadrillion tons! To make this enormous number more tangible: If we consider an average human weight of 70 kg, this mass would equal about 7.1 trillion people – over 9,000 times the current world population. If 1 ton of limestone equaled 1 car, every person on Earth could theoretically receive about 62.5 million cars. These comparisons help show just how massive and impressive the Earth’s limestone reservoirs really are. From tropical coral reefs to icy highlands, limestone shapes landscapes and supports industries worldwide. Conclusion The next glass of milk or calcium supplement in your hand carries more than just nutrition – it tells the story of ancient seas, tiny organisms, and geological forces working over millions of years. Calcium carbonate is not just a building block of our bodies; it’s a witness to Earth’s long history.
