{ "spore": "profile", "id": "sterling-silver", "spore_version": "0.2", "family": "precious-metals", "name": "Sterling silver", "abbreviation": "Ag 92.5 Cu 7.5", "role": "conductor / jewellery and joining alloy", "category": "metals", "type": "precious-metals", "summary": "Sterling silver is an alloy of 92.5% silver and 7.5% copper, the standard silver alloy for jewellery and silverware. The copper makes it harder and stronger than fine silver, at some cost in electrical conduction. A supplier data sheet for a 0.5 mm as-rolled disk gives a density of 10.4 g/cm3, a melting range of 788 to 891 degC and an electrical resistivity of 1.8 microohm cm. Spacecraft data for this exact alloy were not found in this run, so the space links in this file come from silver-copper brazing and solar-cell paste.\n", "best_for": "Silver-rich alloy that is harder than fine silver and still conducts electricity (supplier resistivity 1.8 µOhmcm, as-rolled disk)", "weakest_at": "Tarnishing in sulphur-bearing air and corrosion; no sterling-specific atomic-oxygen or tarnish rate was found in a source we could open", "identity": { "formula": "Ag 92.5, Cu 7.5 (by weight), a silver-copper alloy", "designations": [], "source": "goodfellow-sterling", "where": "Properties common to all products in this list: composition \"Ag 92.5/Cu 7.5\"; Total Materia composition \"Ag 92.500%, Cu 7.500%\" and heat-treatment line" }, "tags": { "environments": [], "stresses": [], "applications": [ "in-space-manufacturing", "solar-arrays" ] }, "properties": [ { "benchmark": "density", "label": "Density of a 0.5 mm as-rolled sterling disk", "value": 10.4, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "form": "0.5 mm disk, as rolled", "temperature": "not stated on the page" }, "method": "Value printed in the physical properties table of the supplier page", "status": "ground", "note": "Total Materia prints 10.4 kg/dm3 for 0 to 30 degC for the same composition.", "source": "goodfellow-sterling", "where": "Physical Properties table", "source_detail": { "title": "Sterling silver disk (Ag92.5-Cu7.5), material properties (Goodfellow)", "id": "Goodfellow Ag92.5-Cu7.5 disk, as-rolled, 0.5 mm", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025, "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "melting_point", "label": "Melting range of sterling silver", "value": 788, "value_high": 891, "bound": "range", "unit": "degC", "scope": "material", "conditions": { "form": "0.5 mm disk, as rolled" }, "method": "Range printed in the thermal properties table of the supplier page", "status": "ground", "note": "Total Materia prints 820 to 890 degC with no stated condition; that wider-looking range is not used here.", "source": "goodfellow-sterling", "where": "Thermal Properties table", "source_detail": { "title": "Sterling silver disk (Ag92.5-Cu7.5), material properties (Goodfellow)", "id": "Goodfellow Ag92.5-Cu7.5 disk, as-rolled, 0.5 mm", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025, "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "electrical_resistivity", "label": "Electrical resistivity of sterling silver", "value": 1.8, "bound": "exact", "unit": "µOhmcm", "scope": "material", "conditions": { "form": "0.5 mm disk, as rolled", "temperature": "not stated on the page" }, "method": "Value printed in the electrical properties table of the supplier page; the temperature coefficient cell is blank", "status": "ground", "source": "goodfellow-sterling", "where": "Electrical Properties table", "source_detail": { "title": "Sterling silver disk (Ag92.5-Cu7.5), material properties (Goodfellow)", "id": "Goodfellow Ag92.5-Cu7.5 disk, as-rolled, 0.5 mm", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025, "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "specific_heat", "label": "Specific heat", "value": 245, "bound": "exact", "unit": "J K-1 kg-1", "scope": "material", "conditions": { "temperature": "23 degC", "form": "0.5 mm disk, as rolled" }, "method": "Printed as 245 at 23 degC in the thermal properties table", "status": "ground", "source": "goodfellow-sterling", "where": "Thermal Properties table", "source_detail": { "title": "Sterling silver disk (Ag92.5-Cu7.5), material properties (Goodfellow)", "id": "Goodfellow Ag92.5-Cu7.5 disk, as-rolled, 0.5 mm", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025, "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "cte", "label": "Coefficient of thermal expansion", "value": 19, "bound": "exact", "unit": "x10-6 K-1", "scope": "material", "conditions": { "temperature_range": "20 to 100 degC", "form": "0.5 mm disk, as rolled" }, "method": "Printed as 19 (x10 to the power -6 per K) in the thermal properties table", "status": "ground", "source": "goodfellow-sterling", "where": "Thermal Properties table", "source_detail": { "title": "Sterling silver disk (Ag92.5-Cu7.5), material properties (Goodfellow)", "id": "Goodfellow Ag92.5-Cu7.5 disk, as-rolled, 0.5 mm", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025, "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, as rolled", "value": 207, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "temper": "as rolled", "form": "0.5 mm disk" }, "method": "Printed in the mechanical properties table of the supplier page; the test standard and temperature are not stated", "status": "ground", "note": "Only the as-rolled figure is entered. Total Materia gives a 280 to 550 MPa range with no temper stated, and that range is not used because it mixes tempers.", "source": "goodfellow-sterling", "where": "Mechanical Properties table", "source_detail": { "title": "Sterling silver disk (Ag92.5-Cu7.5), material properties (Goodfellow)", "id": "Goodfellow Ag92.5-Cu7.5 disk, as-rolled, 0.5 mm", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025, "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "hardness_vickers", "label": "Vickers hardness", "value": 71, "bound": "exact", "unit": "kgf mm-2", "scope": "material", "conditions": { "temper": "as rolled", "form": "0.5 mm disk" }, "method": "Printed in the mechanical properties table of the supplier page", "status": "ground", "source": "goodfellow-sterling", "where": "Mechanical Properties table", "source_detail": { "title": "Sterling silver disk (Ag92.5-Cu7.5), material properties (Goodfellow)", "id": "Goodfellow Ag92.5-Cu7.5 disk, as-rolled, 0.5 mm", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025, "kind": "datasheet", "license": "supplier web page, cited not reproduced" } } ], "corrosion": [], "risks": { "hazards": [ { "text": "PubChem silver record (CID 23954) lists H361f (suspected of damaging fertility), H373 (may cause damage to organs through prolonged or repeated exposure), H400 (very toxic to aquatic life) and H410 (very toxic to aquatic life with long-lasting effects). The record notes that 28.9% (623 of 2154) of reports say silver does not meet GHS hazard criteria.", "ghs": [ "H361f", "H373", "H400", "H410" ], "source": "pubchem-silver", "where": "GHS Hazard Statements and Note in the GHS Classification section" }, { "text": "PubChem copper record (CID 23978) lists H400 and H410 and H302 (21.7%, harmful if swallowed). The record notes that copper does not meet GHS hazard criteria for 52.5% (1818 of 3463) of reports.", "ghs": [ "H302", "H400", "H410" ], "source": "pubchem-copper", "where": "GHS Hazard Statements and Note in the GHS Classification section" } ], "failure_risks": [], "side_effects": [], "handling": [ { "text": "The PubChem silver record says that 28.9% of reports find silver does not meet GHS hazard criteria, so check the supplier safety data sheet for the alloy and form you buy. No safety data sheet for sterling silver itself was read in this run.", "source": "pubchem-silver", "where": "Note in the GHS Classification section" } ], "mitigations": [] }, "uses": [ { "application": "in-space-manufacturing", "device": "Silver-copper-lithium brazing alloy in the Skylab M-552 ethothermic brazing experiment (related braze, not sterling silver)", "example": "NASA's Skylab M-552 brazed a nickel ferrule to a nickel tube with Lithobraze BT, a braze of 71.8% Ag, 28% Cu and 0.2% Li, in a space environment near zero gravity. The source is a 1974 NASA report on the tracer study of the braze flow.", "source": "skylab-m552", "where": "Abstract and body text, NTRS 19750002891" }, { "application": "solar-arrays", "device": "Silver-copper front paste on a silicon heterojunction solar cell (related paste, not sterling silver)", "example": "Fraunhofer ISE reports a silicon heterojunction cell with a silver-copper paste on the front and pure copper paste on the rear, with a total silver consumption of 1.4 milligrams per watt peak. The release does not give the composition of the silver-copper paste.", "source": "fraunhofer2025", "where": "Press release of 28 April 2025, introductory summary and quotation" } ], "supply": [ { "subject": "Silver", "abundance": "USGS: silver is primarily obtained as a byproduct from lead-zinc, copper and gold mines; polymetallic deposits account for more than two-thirds of US and world resources. World mine production 25,300 t in 2024 and an estimated 26,000 t in 2025.", "producers": [ { "country": "Mexico", "share_percent": 24.2, "year": 2025 }, { "country": "Peru", "share_percent": 13.8, "year": 2025 }, { "country": "China", "share_percent": 13.1, "year": 2025 }, { "country": "Bolivia", "share_percent": 5.8, "year": 2025 }, { "country": "Chile", "share_percent": 5.4, "year": 2025 } ], "critical_lists": [ { "list": "USGS Final 2025 List of Critical Minerals (silver added; 90 FR 50494, 7 November 2025)", "listed": true } ], "recycling": "USGS: about 1,000 tons of silver was recovered from new and old scrap in 2025, about 11% of US apparent consumption.", "substitutes": [ "USGS: aluminium and rhodium may replace silver in mirrors and reflecting surfaces; stainless steel and other metals replace silver in some surgical and tableware uses." ], "source": "usgs-mcs2026-silver", "where": "Mineral Commodity Summaries 2026, Silver chapter, World Mine Production and Reserves table (2025e); shares calculated by Space Mushroom from the 26,000 t total; Recycling; Substitutes" }, { "subject": "Copper", "producers": [ { "country": "Chile", "share_percent": 23, "year": 2025 }, { "country": "Congo (Kinshasa)", "share_percent": 13.9, "year": 2025 }, { "country": "Peru", "share_percent": 11.7, "year": 2025 }, { "country": "China", "share_percent": 7.8, "year": 2025 }, { "country": "United States", "share_percent": 4.3, "year": 2025 } ], "critical_lists": [ { "list": "USGS Final 2025 List of Critical Minerals (copper added, 90 FR 50494, 7 November 2025)", "listed": true } ], "recycling": "USGS: old scrap and new scrap provided about 160,000 t and 760,000 t of copper in 2025; brass and wire-rod mills accounted for about 80% of copper recovered from scrap.", "substitutes": [], "source": "usgs-mcs2026-copper", "where": "Mineral Commodity Summaries 2026, Copper chapter, World Mine and Refinery Production table (2025e, 23,000 kt world total); shares calculated by Space Mushroom; Critical Minerals and Recycling paragraphs" } ], "media": [], "documents": [ { "title": "Goodfellow sterling silver disk (Ag92.5-Cu7.5) properties page", "type": "datasheet", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025 }, { "title": "Total Materia: Ag 925 Cu (PX Group SA product data sheet)", "type": "database", "url": "https://www.totalmateria.com/en-us/material/3308698", "year": 2026 }, { "title": "ASM Alloy Digest Ag-11: Sterling Silver, Silver-Copper Alloy (abstract only; full text paywalled)", "type": "database", "url": "https://dl.asminternational.org/alloy-digest/article/34/2/Ag-11/4889/STERLING-SILVERSilver-Copper-Alloy", "year": 1972 }, { "title": "USGS Mineral Commodity Summaries 2026: Silver", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2026: Copper", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf", "year": 2026 }, { "title": "PubChem: Silver (CID 23954), GHS classification", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Silver", "year": 2026 }, { "title": "PubChem: Copper (CID 23978), GHS classification", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Copper", "year": 2026 }, { "title": "NASA NTRS 19750002891: Radioisotope tracer studies in the NASA Skylab ethothermic brazing experiment M-552", "type": "report", "url": "https://ntrs.nasa.gov/citations/19750002891", "year": 1974 }, { "title": "Fraunhofer ISE press release: silicon heterojunction solar cells with record savings in silver (28 April 2025)", "type": "report", "url": "https://www.ise.fraunhofer.de/en/press-media/news/2025/silicon-heterojunction-solar-cells-realized-with-record-savings-in-silver.html", "year": 2025 } ], "gaps": [ "Elongation at break for the as-rolled disk was printed as less than 41% in the Goodfellow table when read through the rendered page, but that figure is not in the page's static HTML, so it was removed rather than left unverified.", "No thermal conductivity for the 92.5/7.5 alloy was found in a readable source. The Goodfellow page prints none, Total Materia prints none, and the Shapeways data sheet returned HTTP 404 in this run.", "No elastic modulus for sterling silver was read. The silver profile's 82.7 GPa is for pure silver and is not used here.", "The Total Materia yield strength (150 to 500 MPa), tensile range (280 to 550 MPa) and elongation range (5 to 60%) give no temper, so they are not entered. Total Materia's figures for density and melting range are not used because the Goodfellow figures are for a stated form.", "The ASM Alloy Digest Ag-11 full text is paywalled. Only its abstract was read, which gives the minimum silver content of 92.50% for silversmiths' grade. Its physical, tensile and corrosion data were not seen.", "Tarnish and corrosion: a 2015 Heritage Science paper on sulphidation of sterling silver (Storme et al., DOI 10.1186/s40494-015-0054-1) was found by search, but the full text redirected to a publisher login page. No sterling tarnish rate, sulphur test or atomic-oxygen result was entered.", "No space-environment data for sterling silver itself were found: no atomic-oxygen erosion, outgassing, thermal-vacuum, radiation or cryogenic result.", "Brazing alloy composition for BAg-8 (Ag 72, Cu 28, eutectic near 780 degC) was not confirmed in a readable source. The Lucas-Milhaupt Silvaloy 721 page returned HTTP 404 and the MakeItFrom BAg-8 page returned HTTP 403. No AWS A5.8 designation is listed in this file.", "Coin silver (90% Ag) was not covered: no source was read for its composition or properties.", "No UNS, EN, DIN, JIS or ASTM designation for sterling silver was read from a page that prints it, so identity.designations is empty.", "Electrical conductivity in percent IACS was not read in this run, so it is not entered.", "The hazard data are for elemental silver and copper, not a sterling-silver safety data sheet. The PubChem Silver record does not separate the massive, powder and nano forms in the text read in this run.", "Failure modes (for example brazed-joint failure, solder fatigue or silver-copper mixed-tempering effects) were not sourced, so failure_risks is empty.", "The copper EU critical raw materials list status and copper abundance were not checked in this run." ], "story": { "why": "Sterling silver is a copper-hardened silver alloy used in jewellery, silverware and as a conductor where a little strength is needed. The supplier data show a melting range of 788 to 891 degC and a resistivity of 1.8 µOhmcm for an as-rolled disk. Its density of 10.4 g/cm3 is is the figure printed for this disk. In a space context the alloy is not a known flight material in this record; the closest space links are silver-copper brazing and solar-cell paste, which are different compositions.", "uses": [ { "where": "Brazing in space", "line": "A NASA Skylab experiment in 1974 used a silver-copper-lithium braze (71.8% Ag, 28% Cu, 0.2% Li) to join nickel parts in space. It is a related braze, not sterling silver." }, { "where": "Solar-cell paste", "line": "Fraunhofer ISE reports a silicon heterojunction cell with a silver-copper paste on the front and pure copper on the rear, at 1.4 milligrams of silver per watt peak. The composition of the silver-copper paste is not given in the release." } ], "can_do": [ { "label": "Conduct electricity", "line": "The supplier lists a resistivity of 1.8 µOhmcm for the as-rolled disk. Copper in the alloy raises the resistivity above that of pure silver.", "benchmark": "electrical_resistivity", "scope": "material" }, { "label": "Carry load", "line": "The as-rolled disk has a tensile strength of 207 MPa and a Vickers hardness of 71.", "benchmark": "ultimate_tensile_strength", "scope": "material" }, { "label": "Expansion with heat", "line": "The coefficient of thermal expansion is 19 (x10 to the power -6 per K) between 20 and 100 degC.", "benchmark": "cte", "scope": "material" } ], "compare": "No source in this record compares sterling silver with another metal under the same test, so no ranking is made. The alloy is harder than fine silver and is chosen where some strength is needed with silver's conduction. Its values are for a single supplier disk, so they should be checked against the supplier's form and temper.", "compare_rows": [ { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Melting range", "benchmark": "melting_point", "scope": "material" }, { "label": "Electrical resistivity", "benchmark": "electrical_resistivity", "scope": "material" } ], "handling": [ "Check the supplier safety data sheet for the alloy and form. PubChem's silver and copper records classify differently by form.", "Annealing is done at 650 degC for 30 minutes and then quenched under protective gas, per the Total Materia data sheet.", "Sulphur-bearing air tarnishes silver, and no sterling-specific tarnish rate is in this file." ], "good_for": [ "Conduction with some strength. Resistivity 1.8 µOhmcm and tensile strength 207 MPa as rolled.", "Hardness over fine silver. The copper addition gives a Vickers hardness of 71 in the as-rolled disk." ], "watch_out": [ "Tarnish. The copper in the alloy changes how the surface tarnishes; no sourced rate is in this file.", "Space data. No sterling-specific atomic-oxygen, outgassing or thermal-vacuum record was found.", "Form and hazard. Hazard classification depends on form, so check the supplier safety data sheet." ], "verdict": "Sterling silver is a practical silver alloy when some strength is needed alongside conduction. For space use, the file has no sterling-specific test record, so any flight use needs its own data.", "recipe": { "line": "Sterling silver is a silver-copper alloy: 92.5% silver and 7.5% copper by weight. The silver is the base metal and the copper is added to harden it. The alloy is annealed at 650 degC for 30 minutes and quenched under N2+H2 protective gas, according to the Total Materia data sheet.", "parts": [ { "name": "Silver", "symbol": "Ag", "role": "The base metal. It gives the alloy its conduction and its silver colour." }, { "name": "Copper", "symbol": "Cu", "role": "The hardening addition. It raises hardness and strength over fine silver; the ASM abstract notes copper lowers electrical and thermal conductivity." } ] }, "risk_groups": [ { "title": "For people", "lead": "The alloy itself has no GHS classification in a record we could read. The elements it is made of carry hazard codes in PubChem, and the classification varies by form.", "points": [ { "label": "Silver", "line": "PubChem's silver record lists suspected reproductive and organ toxicity codes, and aquatic toxicity codes. 28.9% of company reports say silver does not meet GHS hazard criteria." }, { "label": "Copper", "line": "PubChem's copper record lists aquatic toxicity codes and H302 (harmful if swallowed, 21.7%). 52.5% of reports say copper does not meet GHS hazard criteria." } ], "level": 1, "verdict": "Depends on form and supplier" }, { "title": "If it fails", "lead": "No failure record for sterling silver was read in this run, so this group is left as a gap.", "points": [ { "label": "Gap", "line": "The space links in this file are for a silver-copper-lithium braze and a silver-copper solar paste, not for a sterling part flown in orbit." } ] }, { "title": "Handling and storage", "points": [ { "label": "Safety data sheet", "line": "Check the supplier safety data sheet for the alloy and form you buy, since PubChem's classification depends on the notifier." } ] } ] }, "updated": "2026-10-26", "review": { "status": "draft", "method": "assistant", "checked_values": 7, "unreachable": 4, "caveats": 4, "note": "Written by an AI assistant on 2026-10-26. Goodfellow values were read from the page's table in this run. Total Materia composition and anneal condition were read from its page; its ranges were not used because they mix tempers or give no condition. Unreachable in this run: Shapeways data sheet (404), Lucas-Milhaupt Silvaloy 721 page (404), MakeItFrom BAg-8 page (403), Storme et al. full text (publisher login). ASM Ag-11 full text is paywalled. Caveats: the alloy is single-sourced for properties; copper producer shares are calculated; the space links are for related alloys, not sterling." }, "sources": { "goodfellow-sterling": { "title": "Sterling silver disk (Ag92.5-Cu7.5), material properties (Goodfellow)", "id": "Goodfellow Ag92.5-Cu7.5 disk, as-rolled, 0.5 mm", "url": "https://www.goodfellow.com/usa/sterling-silver-disc-ag92-5-cu7-5-group", "year": 2025, "kind": "datasheet", "license": "supplier web page, cited not reproduced" }, "asm-ag11": { "title": "STERLING SILVER: Silver-Copper Alloy (ASM Alloy Digest Ag-11), abstract", "id": "ASM Alloy Digest, Ag-11, vol. 34 issue 2 (abstract read; full text paywalled)", "url": "https://dl.asminternational.org/alloy-digest/article/34/2/Ag-11/4889/STERLING-SILVERSilver-Copper-Alloy", "year": 1972, "kind": "handbook", "license": "ASM International, abstract cited only" }, "totalmateria-ag925": { "title": "Ag 925 Cu (PX Group SA product data sheet), Total Materia", "id": "Total Materia material 3308698", "url": "https://www.totalmateria.com/en-us/material/3308698", "year": 2026, "kind": "database", "license": "database page, cited not reproduced" }, "usgs-mcs2026-silver": { "title": "Mineral Commodity Summaries 2026: Silver", "id": "U.S. Geological Survey, February 2026", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-mcs2026-copper": { "title": "Mineral Commodity Summaries 2026: Copper", "id": "U.S. Geological Survey, February 2026", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "pubchem-silver": { "title": "PubChem compound record: Silver (CID 23954)", "id": "CID 23954; CAS 7440-22-4", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Silver", "year": 2026, "kind": "database", "license": "public domain (NCBI)" }, "pubchem-copper": { "title": "PubChem compound record: Copper (CID 23978)", "id": "CID 23978", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Copper", "year": 2026, "kind": "database", "license": "public domain (NCBI)" }, "skylab-m552": { "title": "Radioisotope tracer studies in the NASA Skylab ethothermic brazing experiment M-552", "id": "NTRS 19750002891", "url": "https://ntrs.nasa.gov/citations/19750002891", "year": 1974, "kind": "report", "license": "public domain (NASA)" }, "fraunhofer2025": { "title": "Silicon Heterojunction Solar Cells Realized with Record Savings in Silver (press release)", "id": "Fraunhofer ISE, 28 April 2025", "url": "https://www.ise.fraunhofer.de/en/press-media/news/2025/silicon-heterojunction-solar-cells-realized-with-record-savings-in-silver.html", "year": 2025, "kind": "web", "license": "press release, cited not reproduced" }, "wikipedia-sterling": { "title": "Sterling silver (Wikipedia), composition and history only", "id": "Lead section, composition", "url": "https://en.wikipedia.org/wiki/Sterling_silver", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/sterling-silver/" }