Pezzottaite

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title: "Pezzottaite" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["lithium-minerals", "beryllium-minerals", "cyclosilicates", "gemstones", "trigonal-minerals", "minerals-in-space-group-161", "caesium-minerals", "beryl-group"] description: "Mineral species" topic_path: "general/lithium-minerals" source: "https://en.wikipedia.org/wiki/Pezzottaite" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Mineral species ::

::data[format=table title="Infobox mineral"]

Field	Value
name	Pezzottaite
category	Cyclosilicate minerals
image	Pezzottaïte, amazonite, zircon 1.jpeg
imagesize	260px
formula	Cs(Be2Li)Al2Si6O18
IMAsymbol	Pez
system	Trigonal
class	Ditrigonal pyramidal (3m)
(same H-M symbol)
symmetry	R3c
color	Raspberry red, orange-red, pink
habit	Flattened, tabular, equant, aggregate
cleavage	Imperfect; basal
fracture	Conchoidal to uneven
mohs	8
tenacity	Brittle
luster	Vitreous
refractive	1.601 to 1.620
opticalprop	Uniaxial
birefringence	−0.008 to 0.011
pleochroism	Moderate dichroic
streak	White
gravity	3.10
references
::

| name = Pezzottaite | category = Cyclosilicate minerals | boxwidth = | boxbgcolor = | image = Pezzottaïte, amazonite, zircon 1.jpeg | imagesize = 260px | caption = | formula = Cs(Be2Li)Al2Si6O18 | IMAsymbol = Pez | strunz = | system = Trigonal | class = Ditrigonal pyramidal (3m) (same H-M symbol) | symmetry = R3c | color = Raspberry red, orange-red, pink | habit = Flattened, tabular, equant, aggregate | twinning = | cleavage = Imperfect; basal | fracture = Conchoidal to uneven | mohs = 8 | tenacity = Brittle | luster = Vitreous | refractive = 1.601 to 1.620 | opticalprop = Uniaxial | birefringence = −0.008 to 0.011 | pleochroism = Moderate dichroic | streak = White | gravity = 3.10 | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = | other = | references =

Pezzottaite, marketed under the name raspberyl or raspberry beryl, is a mineral species first recognized by the International Mineralogical Association in September 2003. Pezzottaite is a caesium analogue of beryl, a silicate of caesium, beryllium, lithium and aluminium, with the chemical formula Cs(Be2Li)Al2Si6O18. Named after Italian geologist and mineralogist Federico Pezzotta, pezzottaite was first thought to be either red beryl or a new variety of beryl ("caesium beryl"); unlike actual beryl, however, pezzottaite contains lithium and crystallizes in the trigonal crystal system rather than the hexagonal system.

Appearance

Colors include shades of raspberry red to orange-red and pink. Recovered from miarolitic cavities in the granitic pegmatite fields of Fianarantsoa province, southern Madagascar, the pezzottaite crystals were small—no more than about 7 cm in their widest dimension—and tabular or equant in habit, and few in number, most being heavily included with growth tubes and liquid feathers. Approximately 10 percent of the rough material would also exhibit chatoyancy when polished. Most cut pezzottaite gems are under one carat (200 mg) in weight and rarely exceed two carats (400 mg).

Physical and optical properties

With the exception of hardness (8 on Mohs scale), the physical and optical properties of pezzottaite—i.e., specific gravity 3.10 (average), refractive index 1.601 to 1.620, birefringence 0.008 to 0.011 (uniaxial negative)—are all higher than typical beryl. Pezzottiate is brittle with a conchoidal to irregular fracture, and streaks white. Like beryl, it has an imperfect to fair basal cleavage. Pleochroism is moderate, from pink-orange or purplish pink to pinkish purple. Pezzottaite's absorption spectrum, as seen by a hand-held (direct vision) spectroscope, features a band at 485–500 nm with some specimens showing additional weak lines at 465 and 477 nm and a weak band at 550 to 580 nm.

Deposits

The mineral was recovered from granitic pegmatite fields of Fianarantsoa province, southern Madagascar. Most (if not all) of the Madagascan deposits have since been exhausted. Pezzottaite has been found in at least one other locality, Afghanistan: this material was first thought to be caesium-rich morganite (pink beryl). Like morganite and red beryl, pezzottaite is believed to owe its color to radiation-induced color centres involving trivalent manganese. Pezzottaite will lose its color if heated to 450 °C for two hours, but the color can be restored with gamma irradiation.

References

References

1. Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
2. [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Pezzottaite Mineralienatlas]
3. [http://www.mindat.org/min-25652.html Mindat.org: Pezzottaite]
4. [http://www.webmineral.com/data/Pezzottaite.shtml Webmineral.com]
5. "Pezzottaite from Ambatovita, Madagascar: A New Gem Mineral".

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