scawtite

{{infobox mineral

| name = Scawtite

| image = Scawtite.jpg

| alt =

| caption =

| category = Silicate mineral

| formula = Ca₇(Si₃O₉)₂CO₃·2H₂O

| IMAsymbol = Scw{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}

| strunz = 9.CK.15

| dana = 64.2.1.1

| system = Monoclinic

| class = Prismatic (2/m)
(same H-M symbol)

| symmetry = C2/m

| unit cell = a = 10.12 Å, b = 15.18 Å
c = 6.62 Å; β = 100.55°; Z = 2

| color = Colorless

| habit = Platy - micaceous, parallel to radiating clusters

| twinning =

| cleavage = Perfect on {001}, poor on {010}

| fracture =

| tenacity =

| mohs = 4–5

| luster = Vitreous

| streak =

| diaphaneity = Transparent

| gravity = 2.77

| density =

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| opticalprop = Biaxial (+)

| refractive = n_α = 1.597 - 1.603 n_β = 1.606 - 1.609 n_γ = 1.618 - 1.621

| birefringence = δ = 0.021

| pleochroism =

| 2V = Measured from 74° to 78°

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| references = [http://www.handbookofmineralogy.com/pdfs/scawtite.pdf Scawtite in the Handbook of Mineralogy][http://www.mindat.org/min-3552.html Scawtite on Mindat.org][http://www.webmineral.com/data/Scawtite.shtml#.VoaFYrY4HRY Scawtite data on Webmineral]

}}

Scawtite is a hydrous calcium silicate mineral with carbonate, formula: Ca₇(Si₃O₉)₂CO₃·2H₂O. It crystallizes in the monoclinic crystal system as thin plates or flat prisms.

Scawtite was first described in 1929 for an occurrence at Scawt Hill in Northern Ireland.

Scawtite occurs as in skarns and hydrothermal veins in limestone. Associated minerals include melilite, spurrite, tobermorite, thomsonite, larnite, grossular, bultfonteinite, calcite, analcime, foshagite and hillebrandite.