Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
trigonaluncommonSilicates
Tourmaline
(Na,Ca)(Mg,Fe,Li,Al)3Al6(BO3)3Si6O18(OH)4
This image displays a cluster of well-formed, prismatic crystals of pink to reddish-pink tourmaline, likely elbaite, exhibiting distinct striations along their length.
Tourmaline Physical Properties
Mohs Hardness
7Crystal System
trigonalLuster
vitreousStreak Color
whiteCleavage
indistinct/poor basalFracture
conchoidal to unevenSpecific Gravity
3.02Colors
pink, red, green, blue, black, brown, yellow, colorlessTransparency
transparentType Locality
Tourmaline Queen Mine, Pala District, San Diego County, California, USAMineral Group
SilicatesUses
jewelry, collector, industrialAssociated Minerals
quartz, feldspar, lepidolite, spodumene, berylRarity
uncommonGeological Context
Tourmaline typically forms in igneous rocks, particularly granitic pegmatites, where it crystallizes from boron-rich hydrothermal fluids during the late stages of magmatic differentiation. It can also occur in some metamorphic rocks.
