| Stolzite | |
|---|---|
 Stolzite, Broken Hill, Australia (size: 3.6 x 3.0 x 2.6 cm) | |
| General | |
| Category | Tungstate minerals |
| Formula | PbWO4 |
| IMA symbol | Sz[1] |
| Strunz classification | 7.GA.05 |
| Crystal system | Tetragonal |
| Crystal class | Dipyramidal (4/m) H-M symbol: (4/m) |
| Space group | I41/a |
| Unit cell | a = 5.461, c = 12.049 [Å]; Z = 4 |
| Identification | |
| Color | Reddish brown, brown, yellowish gray, smoky gray, straw-yellow, lemon-yellow; may be green, orange, red |
| Crystal habit | Crystals dipyramidal to tabular |
| Cleavage | Imperfect on {001}, indistinct on {011} |
| Fracture | Conchoidal to uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 2.5–3 |
| Luster | Resinous, subadamantine |
| Streak | White |
| Diaphaneity | Translucent to transparent |
| Specific gravity | 8.34 |
| Optical properties | Uniaxial (−) |
| Refractive index | nω = 2.270 nε = 2.180 – 2.190 |
| Birefringence | δ = 0.090 |
| References | [2][3][4][5] |
Stolzite is amineral, aleadtungstate; with theformula PbWO4. It is similar to, and often associated with,wulfenite which is the same chemical formula except that the tungsten is replaced bymolybdenum. Stolzite crystallizes in thetetragonal crystal system and isdimorphous with themonoclinic formraspite.[4]
Lead tungstate crystals have the optical transparency of glass combined with much higher density (8.28 g/cm3 vs ~2.2 g/cm3 forfused silica). They are used asscintillators inparticle physics because of their shortradiation length (0.89 cm), lowMolière radius (2.2 cm), quick scintillation response, and radiation hardness.[6] Lead tungstate crystals are used in theCompact Muon Solenoid's electromagnetic calorimeter.[6]
It was first described in 1820 byAugust Breithaupt, who called it Scheelbleispath and then byFrançois Sulpice Beudant in 1832, who called it scheelitine. In 1845,Wilhelm Karl Ritter von Haidinger coined the name stolzite for an occurrence in theOre Mountains,Bohemia (today theCzech Republic), naming it afterJoseph Alexi Stolz ofTeplice in Bohemia.[4][5] It occurs in oxidized hydrothermal tungsten-lead ore deposits typically in association withraspite,cerussite,anglesite,pyromorphite andmimetite.[3]
CMS has chosen lead tungstate scintillating crystals for its ECAL. These crystals have short radiation (X0 = 0.89 cm) and Moliere (2.2 cm) lengths, are fast (80% of the light is emitted within 25 ns) and radiation hard (up to 10 Mrad).
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