AAA Diamond Apophyllite on Blue Chalcedony with Peach Stilbite

AAA Diamond Apophyllite on Blue Chalcedony with Peach Stilbite

Overview

This striking specimen features a cluster of high-clarity “diamond” apophyllite crystals emerging from a deep blue chalcedony matrix, accented by soft peach stilbite blades. The combination of sharp, reflective apophyllite terminations and the textured botryoidal chalcedony creates a strong visual contrast, while the stilbite adds a secondary mineral layer that enhances both structure and rarity.

The piece has a natural, sculptural form with a raised crystal cluster sitting prominently on the surface, making it ideal as a display specimen.

Key Features

Minerals: Apophyllite, Chalcedony (Quartz), Stilbite

Grade: AAA (excellent crystal definition, strong lustre, balanced composition)

Colour:

Colourless to transparent apophyllite

Deep blue-grey chalcedony base

Soft peach stilbite crystals

Crystal System:

Apophyllite: Tetragonal

Stilbite: Monoclinic

Formation:

Botryoidal chalcedony base formed first

Apophyllite crystallised from hydrothermal fluids

Stilbite formed later, depositing between and around existing crystals

Lustre:

Apophyllite: High vitreous (glass-like)

Chalcedony: Waxy to dull

Stilbite: Pearly to vitreous

Transparency:

Apophyllite: Transparent

Chalcedony: Opaque to translucent

Stilbite: Translucent

Dimensions

Weight: 366 grams

Size: 8.5 cm x 6.5 cm

Geological & Scientific Notes

This is a classic Deccan Trap–style zeolite formation:

Chalcedony (SiO₂) forms as a microcrystalline silica lining volcanic cavities, often developing botryoidal (rounded) textures

Apophyllite (hydrated potassium calcium silicate) crystallises from later hydrothermal fluids, forming well-defined prismatic crystals with flat terminations

Stilbite (a zeolite mineral) forms during the later stages, typically appearing as sheaf-like or blade clusters

The layering seen here reflects multiple stages of mineral deposition, making it a great example of sequential crystal growth in volcanic environments.

Why This Piece Stands Out

Strong contrast: dark chalcedony vs glass-clear apophyllite

Presence of peach stilbite adds rarity and collector appeal

Large, well-terminated apophyllite crystals with high reflectivity

Sculptural, display-ready formation

Multi-mineral composition (more desirable than single-mineral pieces)

Care & Handling

Handle with care — apophyllite and stilbite are relatively delicate

Avoid water exposure (stilbite can be sensitive)

Clean with a soft dry brush or air blower

Store away from harder minerals to prevent scratching