traded spot and derivative markets. Hard and soft commodities Soft commodities are goods that are grown, such as wheat, or rice. Hard commodities are mined. Examples include gold, silver, helium, and oil. Energy commodities include electricity, gas, coal and oil. Electricity has the particular characteristic that it is usually uneconomical to store, and must therefore be consumed as soon as it is produced. Commoditization Commoditization occurs as a goods or services market loses differentiation across its supply base, often by the diffusion of the intellectual capital necessary to acquire or produce it efficiently. As such, goods that formerly carried premium margins for market participants have become commodities, such as generic pharmaceuticals and DRAM chips. An article in The New York Times cites multivitamin supplements as an example of commoditization; a 50 mg tablet of calcium is of equal value to a consumer no matter what company produces and markets it, and as such, multivitamins are now sold in bulk and are available at any supermarket with little brand differentiation. Following this trend, nanomaterials are emerging from carrying premium profit margins for market participants to a status of commodification. There is a spectrum of commoditization, rather than a binary distinction of "commodity versus differentiable product". Few products have complete undifferentiability and hence fungibility; even electricity can be differentiated in the market based on its method of generation (e.g., fossil fuel, wind, solar), in markets where energy choice lets a buyer opt (and pay more) for renewable methods if desired. Many products' degree of commoditization depends on the buyer's mentality and means. For example, milk, eggs, and notebook paper are not differentiated by many customers; for them, the product is fungible and lowest price is the main decisive factor in the purchasing choice. Other customers take into consideration other factors besides price, such as environmental sustainability and animal welfare. To these customers, distinctions such as "organic versus not" or "cage free versus not" count toward differentiating brands of milk or eggs, and percentage of recycled content or Forest Stewardship Council certification count toward differentiating brands of notebook paper. Global commodities trading company This is a list of companies trading globally in commodities, descending by size as of October 28, 2011. Vitol Glencore International AG Trafigura Cargill Salam Investment Archer Daniels Midland Gunvor (company) Mercuria Energy Group Noble Group Louis Dreyfus Group Bunge Limited Wilmar International Olam International Rochel International Commodity trade In