This glossary contains terms and definitions used throughout the site. For complete information consult the original source material (for full references check the site’s bibliography).
Accession - the formal process used to accept legal responsibility as a repository for, and to record a specimen or group of specimens as part of the Museum’s collections. Can also be used as a noun, to refer to the object or groups of objects themselves.
Accession number – a number or other unique identifier applied to an object or objects, creating an immediate, brief, and permanent record for objects added to the collection from the same source at the same time, and for which the institution accepts custody, right, or title.
Adhesive - any substance capable of bonding other substances together by surface attachment. (Elder et.al. 1997)
Agents of deterioration – Those forces that contribute to the ultimate destruction of museum objects over a period of time; for natural history specimens, generally considered to be intrinsic factors, physical forces, fire, water, inappropriate relative humidity, in appropriate temperature, pests, criminals, contaminants, and radiation (including light). (Cato et.al. p.18)
Alabaster - a term applied to fine translucent varieties of carbonate or sulphate of lime, especially to the pure white varieties of the later (OED). (Referenced in some of fossil preparation’s historical documentation e.g. Hermann). Not commonly used in modern fossil preparation methods.
Butvar - registered trademark for a series polyvinyl butyral resins. They are designed to be transparent, colorless, UV resistant and non-yellowing. When exposed to UV light in the presence of oxygen Butvars tend to crosslink and become insoluble. They come in a wide range of molecular weights but B-76 and B-98 are most commonly used in fossil preparation as a consolidant or, sometimes, adhesive. (Conservation & Art Material Encyclopedia Online)
Carbowax® - A registered trademark for a series of translucent polyethylene glycols (PEG) and methoxypolyethylene glycols. The water-soluble Carbowax products are available in a range of viscosities from a honey-like solution to a hard wax-like block. In fossil preparation Carbowax is use for temporary supports, filling voids during molding and other uses. Carbowax will remain somewhat tacky and can retain dirt that darkens and discolors over time. (Conservation & Art Material Encyclopedia Online)
Carpenter’s glue – historically, adhesives based on the milk protein casein, which is precipitated out of milk using the acetic acid in vinegar (i.e. the solid curds as opposed to the liquid whey). Casein was first used as a wood glue in Switzerland in the late 1800s (Wikipedia). Modern references to carpenter’s glue may allude to Elmer’s yellow PVAC carpenter’s glue.
Catalog – The curatorial process of classifying and documenting objects, usually in complete descriptive detail, resulting in extensive information in the form of cards, files, publications, and automated data. (Porter, 1985, p.12)
Clastic - Clastic rocks are composed of fragments, or clasts, of pre-existing rock. The term is most commonly, but not uniquely, applied to sedimentary rocks. (Wikipedia)
Conservation – The application of science to the examination and treatment of museum objects [and specimens] and to the study of the environments in which they are placed. This involves activities such as preventive conservation, examination, documentation, treatment, research and education. (SPNHC, 1994)
Coating - a surface skin application of a polymer. (Elder et.al. 1997)
Consolidant - an adhesive, often in a volatile carrier solvent, applied to soak into a specimen and force subsurface adhesion. (Elder et.al. 1997)
Copolymer - a preparation made from two or more different monomers. (Elder et.al. 1997)
Corrosive sublimate - mercuric chloride (bichloride or perchloride of mercury), a white crystalline powder, which acts as a violent poison (OED). Referenced in some of the early historical documentation of fossil preparation.
Cross-linkage - the formation of bonds between otherwise unattached polymer chains; A polymer cross-links when chemical bonds are formed between molecules resulting in a three dimensional network. Cross-linking may result in shrinking or degradation of the polymer or renders affected materials insoluble. (Elder et.al. 1997; Horie Adhesives Workshop)
Curate/curation - The process whereby specimens or artifacts are identified and organized according to discipline-specific recommendations using the most recently available scientific literature and expertise; a primary objective of this process is to verify or add to the existing documentation for these objects, and to add to knowledge. (SPNHC, 1994)
Cyanoacrylate - A thermoplastic polymer commonly used as a fast-setting, strong adhesive. Most commercial formulations also contain stabilizers, thickeners and catalysts. The glues set rapidly (5 seconds - 3 minutes) upon exposure to ultraviolet radiation or moisture. When cured, they form an extremely strong bond that is fairly insoluble. Some cyanoacrylates may lose adhesive strength with time. Ultraviolet light and contact with alkaline materials (e.g. some stone) will accelerate the degradation process. (Conservation & Art Material Encyclopedia Online)
Cyclododecane - A white, cyclic hydrocarbon (C12H24), one of a class of volatile waxy solids. The high vapor pressure of CDD causes it to sublimate, passing from a solid to a vapor at room temperature. It has become increasingly widely used in the field of art conservation and fossil preparation as a temporary consolidant, masking material and isolating layer.
Dextrin - a soluble gummy substance into which starch is converted when subjected to a high temperature, or to the action of dilute alkalis or acids. Also called British gum or leiocome (OED). (referenced in some of fossil preparation’s historical documentation e.g. Hermann). Not commonly used in modern fossil preparation methods.
Dispersion - a suspension of polymer particles in a solvent, usually water, in which the particles are suspended but will not dissolve. (Elder et.al. 1997)
Emulsion - very similar to a dispersion, often distinguished by a larger particle size. (Elder et.al. 1997)
Ethafoam ® – a registered trademark for a polyethylene foam produced by Dow. This material is ideally suited as a component material in products requiring a shock absorption, vibration dampening, and as a material for cushioning.
Excelsior - a trade name for short thin curled shavings of soft wood used for stuffing cushions, mattresses, etc. (OED). (Referenced in some of fossil preparation’s historical documentation e.g. Hermann). Not commonly used in modern fossil preparation methods.
Field – in a record, a specified area for a particular category of data. In a database, the smallest unit of data that can be referred to (Cato et al, 2003). In collecting, often used to refer to items created at the time the specimen was collected (e.g. field number, field notes, field jacket), or to the general process of collecting (e.g. fieldwork, in the field)
Fossil - organisms or fragments, impressions, or traces of organisms preserved in rock (Cato et al, 2003); they are formerly organic specimens that have gone through a process of complete or partial replacement of organic material by inorganic material.
Gelatin – A mixture of proteins prepared via boiling, collagen obtained from animal tissues (skin, tendons, ligaments, the matrix of bones, etc.) is converted when treated with hot water for some time. Gelatine is amorphous, brittle, without taste or smell, transparent, and of a faint yellow tint (OED). (referenced in some of fossil preparation’s historical documentation e.g. Hermann). Not commonly used in modern fossil preparation methods.
Glass transition temperature (Tg) - temperature at which a thermoplastic polymer changes from a brittle, glassy state to a plastic state. The higher the Tg, the more brittle the polymer is at room temperature; the lower the Tg, the more likely the polymer is to flow or fail as an adhesive at room temperature.
Hide glue – A strong, liquid adhesive consisting primarily of gelatin and other protein residues of collagen, keratin, or elastin. Hide glue has been made from ancient times from skins of animals (goats, sheep, goats, cattle, horses, etc.). These agglutinating materials are hydrolyzed and broken down in boiling water; the cooled solution yields a jelly-like substance which is gelatin or glue. The water soluble glue occurs in a wide variety of forms and colors ranging from transparent to opaque and white to brown. Commonly made from rabbit skin and parchment clippings. Hide glues have historically been used as an adhesive or consolidant but is not recommended as a modern fossil preparation material.
Hydrolysis - the reaction of materials with water, causing hydration and swelling of materials; often irreversible. (Elder et.al. 1997)
In-situ – A Latin term meaning in the natural or original position or place.
Integrated Pest Management – Bringing together two or more methods of control into a harmonized system designed to maintain pests at levels below those at which they cause harm – a system that must rest on firm ecological principles and approaches. (Romoser, W.S. 1973. The Science of Entomology. Macmillan Publishers, New York)
Library life - The library life in the field of mold making is defined as the storage stability of a mold and how long such a mold can be stored for eventual use without degradation (Dow Corning website).
Material Safety Data Sheet (MSDS) – Available from manufacturers these documents include data on volatility, flammability, toxicity and other safety-related information concerning a specific chemical or material. (Rose, et.al. 1995. p.448)
Microcrystalline wax - A chemically-inert, high molecular weight hydrocarbon wax that has a fine crystalline structure. In general, a stronger adhesive than paraffin wax. (Conservation & Art Material Encyclopedia Online)
Modeling clay – may refer to natural clay minerals, oil-based clays, or polymer clays. Natural clay minerals are water based and can be fired at high temperatures to produce ceramics. Oil-based clays (e.g. Plastilin™, Plasteline™, Plasticine™, Plastilina™) are made from combinations of oils, waxes and clay minerals and remain malleable for extended periods: they cannot be fired and are often used for molding and casting details. Polymer clays (e.g. Fimo™, Sculpey™, Modello™) generally contain no clay minerals and will harden when baked at low temperatures.,.
Monomer - a simple molecular unit that can react to form a polymeric chain or compound. (Elder et.al. 1997)
Morphology – (1) the branch of biology dealing with the form and structure of plants and animals, (2) the form and structure of an organism considered as a whole. (Random House College Dictionary. 1975. Random House, Inc., New York, p.1568.)
Mudstone (also called mudrock) - is a fine grained sedimentary rock whose original constituents were clays or muds. This finely bedded material that splits readily into thin layers is called shale, as distinct from mudstone. Mud rocks, such as mudstone and shale comprise some 65% of all sedimentary rocks. Mudstone looks like hardened clay and, depending upon circumstances under which it was formed, it may show cracks or fissures, like a sun-baked clay deposit. (Wikipedia)
Oxidation - a chemical change based on a reaction with oxygen, often degradative. (Elder et.al. 1997)
Paraffin - A white, translucent odorless hydrocarbon wax that is chemically inert and odorless. (Referenced in some of fossil preparation’s historical documentation e.g. Hermann). Not commonly used in modern fossil preparation methods.
Plasticizer - a material incorporated in an adhesive to increase its flexibility, workability, or distensibility. The addition of a plasticizer may cause a reduction in melt viscosity, lower the transition temperature, or reduce the elasticity of the solidified adhesive. (Elder et.al. 1997)
Polyester resin - A thermoplastic or thermosetting resin made by the reaction of an ester of dihydric alcohol and terephthalic acid. When catalyzed, polyesters can harden at room temperature and pressure with very little shrinkage to produce a clear, colorless block or film. Commonly used in fossil preparation for casting. (Conservation & Art Material Encyclopedia Online)
Polymer - a large molecule formed by the linking together of many repeated units of the same small molecules (monomers) by normal covalent bonds; may be linear or nonlinear (branched). (Elder et.al. 1997)
Policy – A broad statement outlining the intent of the institution with respect to one or more of its objectives. A governing principle; a framework for carrying out work; a definition of what is to be done. (Alberta Museums Association, 1990, p.335)
Polyurethane - a family of polymers made by a condensation reaction of an organic isocyanate with a compound containing a hydroxyl group, such as glycol. Polyurethanes can be rigid or soft, thermosetting or thermoplastic. Additionally, they react with isocyanates to produce a foamed resin. Polyurethane foams are used in fossil preparation for casting. (Conservation & Art Material Encyclopedia Online)
Polyvinyl acetate (PVAC) - a colorless, nontoxic thermoplastic resin prepared by the polymerization of vinyl acetate, it is one of the most widely used water-dispersed resins. Polyvinyl acetate water-based emulsions are commonly known as “white glues”. Setting is accomplished by the removal of water due to evaporation or absorption into a substrate. PVAC resins produce clear, hard films. Additional properties are high initial tack, almost invisible bond line, softening at 30-45C, good biodegradation resistance, poor resistance to creep under load, and low cost. Commonly used as adhesives or barrier layers in fossil preparation. (Conservation & Art Material Encyclopedia Online)
Polyvinyl alcohol (PVOH) - a colorless water soluble thermoplastic resin. When the water evaporates, it forms a flexible transparent material. In general, polyvinyl alcohol is resistant to oils, solvents, greases and fungi. It may be used as an adhesive in fossil preparation. (Conservation & Art Material Encyclopedia Online)
Plaster - 1) Shortened name for plaster of Paris which is composed of calcium sulfate hemihydrate. It is also called calcined gypsum. 2) A powder that forms a pasty mixture with water and dries to a hard impenetrable solid. Plaster is made using several formulations. Some examples of plaster types include: lime plaster (contains calcium oxide); gypsum plaster or gypsum cement (contains calcined and ground gypsum); plaster of Paris (calcined gypsum used for molds, sculpture, casts); stucco (contains gypsum and sand or chalk used for walls, ceilings, decoration). Plaster of Paris is most commonly used in fossil preparation for casting. (Conservation & Art Material Encyclopedia Online)
Preparation – procedures used in the field or in an institution to enhance the utility of a specimen or object for a particular use (SPNHC, 1994). In paleontology this frequently involves the removal of the rocky matrix in which fossils are embedded and subsequent stabilization of the exposed specimen to enable study or exhibit.
Preservation – Actions taken to retard or prevent deterioration or damage to collections materials by control of their environment and/or treatment of their structure in order to maintain them as nearly as possible in an unchanging state. (Duckworth et.al., 1993, p.140)
Preventive Conservation – All actions taken to retard deterioration and prevent damage to cultural property through the provision of optimal conditions of storage, use and handling. (Cato, et.al. p.282)
Procedure – A statement of how a governing principle will be implemented; rules and regulations applied to a framework; a definition of how a policy is to be carried out. (Alberta Museums Association, 1990, p.335)
Provenance – Information that defines a specimen in terms of the specific geographic point of origin as well is the background and history of ownership. Also known as provenience. (Cato, et.al. p.286)
PVA - an ambiguous abbreviation commonly used in the art conservation literature to mean polyvinyl acetate and in the chemical literature for polyvinyl alcohol. The standard abbreviation for polyvinyl acetate is PVAC and the standard abbreviation for polyvinyl alcohol is PVOH or PVAL. (Conservation & Art Material Encyclopedia Online)
Relative Humidity – The ratio, expressed as a percentage, of the amount of water vapor present in the atmosphere to the amount required to saturate it at the same temperature. Varies with temperature. (Alberta Museums Association, 1990, p.335)
Resin - a solid, semi-solid or pseudo-solid organic material that has an indefinite and often high molecular weight, exhibits a tendency to flow when subjected to stress, usually has a softening or melting range, and usually fractures conchoidally. (Elder et.al. 1997)
Reversibility - in conservation science, the ideal ability to remove a substance completely from a treated object, so that no traces or contamination are left. In geological preparation, the practical ability to undo a joint through the use of solvents (Elder et.al. 1997)
Sandstone - Sandstones are clastic in origin. They are formed from cemented grains that may either be fragments of a pre-existing rock or be mono-minerallic crystals. The cements binding these grains together are typically calcite, clays and silica. (Wikipedia)
Shave hook - a plumber’s tool consisting of a blade, commonly triangular, set transversely in a handle, used for scraping metal preparatory to soldering (OED). (referenced in some of fossil preparation’s historical documentation e.g. Hermann). Not commonly used in modern fossil preparation methods.
Shellac – surface coating made from the dark red resinous incrustation produced on certain trees by insect damage. When melted, strained, and formed into irregular thin plates, it this resin is termed shellac (OED). Fresh shellac contains waxes and other impurities that give it a brown color. As it is refined, it may be termed orange shellac and, with further refinement, white shellac.
Silicone - Any of a large group of semi-inorganic polymers based on siloxanes. Silicones can be liquids, gels, and elastomers as well as solid thermoplastic or thermosetting resins. In general, they have excellent heat and chemical resistance and are water repellent. In preparation silicones are used in molding fossil specimens (see silicone resins). (Conservation & Art Material Encyclopedia Online)
Silicone resins - A polymer that contains silicon, carbon, and oxygen. Silicone resins are made by the room-temperature vulcanization (RTV) of silicone oils. They can cure either with moisture in the air (single-component system) or by the addition of a peroxide catalyst (two-component system). Once cured, silicone resins are chemically inert and can exist as elastomers and resins (both thermoset and thermoplastic). They function over a wide temperature range, are water repellent and have very poor adhesion. Silicones are used in fossil preparation as molding compounds. (Conservation & Art Material Encyclopedia Online)
Siltstone - is primarily composed of silt sized particles. Siltstones differ significantly from sandstones due to their smaller pores and higher propensity for containing a significant clay fraction. (Wikipedia)
Solubility - the ability of a substance to dissolve in a given solvent. (Elder et.al. 1997)
Solvent - a substance capable of dissolving another substance (solute) to form a solution. (Elder et.al. 1997)
Specimen – An organism, part of an organism, or naturally-occurring material that has been collected, that may or may not have undergone some preparation treatment. It may exist in its original state, in an altered form, or some combination of the two. A specimen may be comprised of one piece or many related pieces. It may be composed of one physical or chemical component or represent a composite of materials. (SPNHC, 1994)
Stearin - the commercial name of a preparation consisting of purifier fatty acids, used for making candles, and formerly also as a material for statuettes (OED). (referenced in some of fossil preparation’s historical documentation e.g. Hermann). Not commonly used in modern fossil preparation methods.
Subfossil - bones or other organic hard tissues (e.g., shells) that have been subject to sub-aerial weathering and then burial, but have not been subjected to any secondary mineralization (Collins, 1988), often preserved together with associated soft tissue structures, including skin, hair, feathers, and muscle fibers.
Talc - A soft, slippery mineral composed of hydrated magnesium silicate. Sometimes used as a filler for casting materials. (Conservation & Art Material Encyclopedia Online)
Terpolymer - a preparation made from three or more monomers. (Elder et.al. 1997)
Thermoplastic - polymers that can be heated to a plastic state, molded, and then cooled to harden in that shape; theoretically, this can be repeated and new shapes made. (Elder et.al. 1997)
Thermoset - polymers that, once set, cannot be heated and returned to a plastic state. Thermoset adhesives are set through heat, chemical reaction, or use of a catalyst. (Elder et.al. 1997)
Volatilization - the tendency of some materials, such as solvents or plasticizers, to pass to a vapor phase and leave the parent surface or compound. (Elder et.al. 1997)
Type specimen – A type specimen is any specimen that has been designated as the name-bearer in the original published description of a taxon (Art. 73a, International Code of Zoological Nomenclature, 1999
Vinac - A brand name for a series of adhesive emulsions containing polyvinyl acetate. Vinac B-15 has been frequently used in fossil preparation. This formulation is now known as McGean B-15. (Conservation & Art Material Encyclopedia Online)
White glue – A common name for a wide variety of milky white adhesives. Historically may refer to adhesives based on the milk protein casein, which is precipitated out of milk using the acetic acid in vinegar (first used as a wood glue in Switzerland in the late 1800s) or, more recently, for aqueous emulsions of polyvinyl acetate or polyvinyl alcohol commonly used as glues.
Whiting - a preparation of finely powdered chalk (calcium carbonate). Synthetically prepared calcium carbonate may be called precipitated chalk and is usually whiter and finer than whiting. Used for a wide variety of purposes including an inert pigment in paints, flux in glazes, and fillers in adhesives. (referenced in some of fossil preparation’s historical documentation e.g. Hermann). Not commonly used in modern fossil preparation methods.