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What is Natural Cement?
Natural cement
is hydraulic cement made from limestone that has a high clay content (argillaceous limestone). It is different from building lime, which is made from limestone with a lower clay content, in that lime is not hydraulic (does not set under water).

Lime and Natural Cement are both produced by heating limestone to approximately 900 to 11000C, at which point carbon dioxide bound within the stone is released. In the production of lime, the burnt material is quicklime, which is then mixed with water to make building lime, also referred to as hydrated lime, or as lime putty if excess water is used. The process of hydrating quicklime is slaking, and when quicklime is slaked, it crumbles to a fine particle size. The burnt natural cement rock does not slake when mixed with water, however. Instead, it must be crushed into a powder before use. The resulting powder is natural cement, which will set when mixed with water, and hardens through a process of cement hydration.

When lime is used in masonry mortar and renders, it does not set due to being mixed with water, but rather, must react with carbon dioxide in the air in order to cure and harden. This is a slow process, often requiring weeks or months to build significant initial strength.

Portland cement is made from artificial mixtures of limestone, shale, gypsum and other additives. The mixture is heated to approximately 14000C, at which point components fuse to form a clinker. The clinker is then ground to a fine powder that sets when mixed with water.

Hydraulic lime may be made either from blends of lime and pozzolans (such as slag, trass, clay, natural cement, portland cement or ash) or by burning of limestone with naturally occurring silica and/or alumina impurities. It is related to natural cement, but contains excess free lime, allowing the material to be slaked to a fine powder after burning. This excess of lime may reduce durability, lengthen set time and diminish initial resistance to weather, however, particularly in severe exposures such as coastal and cold weather environments.

Natural cement is simply the product of burning and grinding natural cement rock. American natural cement was never a mixture of ingredients such as clay or other pozzolans and lime or hydraulic lime. The use of such artificial mixtures is historically incorrect, therefore, and it is not “replacement-in-kind”. Only authentic Rosendale Natural Cement from Edison Coatings, Inc. is an historically accurate replacement in kind for the restoration of natural cement buildings, structures and monuments.








Dicalcic Silicate (Belite); Produced from argillaceous limestone

Hydration, Crystallization Upon Water Contact

Fast Initial Set, followed by slow, gradual rise to final strength. Strength of natural cement mixtures is easily modulated from low strengths similar to lime mortars to strengths approaching those of modern cements.



Calcium and Magnesium Hydroxide; Produced from limestone.

Forms Calcite and Magnesium Carbonate w/Prolonged Carbon Dioxide Exposure

Slow set and cure, tends to react incompletely below surface.

ASTM C207 (Hydrated Lime)
ASTM C1489 (Lime Putty)


Dicalcic and Tricalcic Silicate, Tricalcium Aluminate; Produced from mixtures of limestone, shale, gypsum, other additives

Hydration, Crystallization upon Water Contact

Controlled Set Times, Rapid Strength Gain

ASTM C150 (Portland Cement)
ASTM C91 (Masonry Cement)


Calcium Hydroxide, Dicalcic Silicate and/or Aluminate. Produced from limestone with silica or alumina impurities, or from blends of lime and pozzolans.

Forms Calcite w/Prolonged Carbon Dioxide Exposure; Hydration, Crystallization upon Water Contact

Slower set than natural and Portland cements, faster than lime/lime putty, slow rise to moderate/low strength

ASTM C1489

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Rosendale Natural Cement Products®
is a registered trademark of Edison Coatings, Inc.

Rosendale Natural Cement Products® are manufactured in the United States of America from 100% American Natural Cement. This is authentic historic material, extracted from historic sources, as originally used in construction of thousands of American and Canadian buildings and structures in the 19th and 20th Centuries. Rosendale 10C Natural Cement and Quick Setting Natural Cement conform to the requirements of ASTM C10/10M-14.

Translantic Natural Cements(TM) are manufactured in the United States of America from USA and globally-sourced components. Translantic Natural Cement conforms to the requirements for Quick-Setting Natural Cement in ASTM C10/10M-14.

Accept No Substitutes!


Edison Coatings, Inc. makes no warranties, express or implied, as to the accuracy or completeness of any of the information contained herein. This publication is offered on a complimentary basis as a service to potential customers or specifiers. While every effort has been made to include complete and accurate information, based on data and information believed to be reliable, it is the sole responsibility of the user to determine its suitability for his own intended use and purposes. Nothing contained herein shall be construed as a warranty or guarantee of any product, process or any other recommendation stated herein. Edison Coatings, Inc. assumes no responsibility for advice given, results obtained, or for any damages whether incidental or consequential, which may be incurred as a direct or indirect result of the use of this information. By proceeding to use this information, user acknowledges and agrees that he is doing so at his own risk, and user indemnifies and holds Edison Coatings harmless against any liabilities, costs or expenses resulting therefrom. Product data and formulations are subject to change without prior notice. All product sales are further governed by the Edison Coatings, Inc. CONDITIONS OF SALE.

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