Analcime from Mont Saint-Hilaire is one of the classic white counterpoints in Canadian mineral collecting: sharp, glassy trapezohedra and rounded modified crystals set against black aegirine, salmon-pink serandite or schizolite, white natrolite, pale feldspar, rhodochrosite, siderite, and a long list of rare alkaline-complex minerals. The best pieces have the unmistakable Mont Saint-Hilaire look—clean, geometric, bright-white analcime crystals perched in highly mineralized cavities where the visual contrast is often as important as crystal size.
Photo: Wikimedia Commons
The locality is the former Poudrette quarry, now Carrière Mont Saint-Hilaire, on the northeastern side of Mont Saint-Hilaire in southern Québec. The mountain is not a volcano but an eroded Cretaceous alkaline pluton, part of the Monteregian Hills. Its fame comes from the East Hill Suite, a peralkaline nepheline-sodalite syenite association cut by pegmatites, breccias, xenolith-rich zones, and small to large cavities. Those cavities provided the open space and late-stage fluids needed to grow the superb crystals that made the quarry one of the world’s great single mineral localities.
For collectors, Mont Saint-Hilaire analcime matters for three reasons. First, it can be very good analcime in its own right: sharp trapezohedra, lustrous white crystals, and unusually large examples for the species. Second, it is part of the locality’s most celebrated aesthetics, especially the orange-pink serandite or schizolite with white analcime association. Third, analcime is a common thread through many Mont Saint-Hilaire parageneses, so a good analcime specimen can also be a gateway into the quarry’s broader story of alkaline minerals, rare elements, and modern systematic collecting.
The finest examples are not merely “white zeolite” specimens. They are Mont Saint-Hilaire specimens: zoned pockets, complex associations, pseudomorphs, and combinations that can carry serious locality significance. A simple sharp analcime on microcline can be handsome; analcime with serandite, aegirine, natrolite, or rare accessory species can be genuinely important.
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Mont Saint-Hilaire lies about 40 kilometers east of Montréal, near the Richelieu River, and the mineral locality of collector fame is the quarry on the northeast side of the mountain. Older labels may read Poudrette quarry, Demix quarry, De-Mix quarry, Uni-Mix quarry, Desourdy quarry, Carrière de Poudrette, or simply Mont Saint-Hilaire. In the collector and mineralogical literature, “Poudrette quarry” remains the most familiar name, even though the present quarry name is Carrière Mont Saint-Hilaire.
The quarry is an active aggregate operation, not a recreational public collecting site. The deposit is an alkaline igneous complex, and the relevant collecting environments include peralkaline syenites, pegmatites, altered pegmatites, igneous breccias, hornfels and marble xenoliths, sodalite-rich rocks, and miarolitic cavities. Analcime is widespread across several of these environments, which explains why it appears both as a principal display mineral and as an associated species on many more complex Mont Saint-Hilaire specimens.
Quarrying exposed the mineralized East Hill Suite and turned Mont Saint-Hilaire from a geologically interesting hill into a mineralogical landmark. Minor scientific notice of the mountain goes back to the nineteenth century, but the locality’s modern importance began after quarrying exposed fresh rock in the early 1960s. Since then, Mont Saint-Hilaire has become one of the richest known single mineral localities, with hundreds of recorded species and dozens of type-locality minerals. Museum collections in Montréal and Ottawa preserve many of the finest examples, and the Canadian Museum of Nature’s Haineault Mont Saint-Hilaire Collection is especially important for documenting the locality at its best.
The quarry history matters to labels. The Demix workings became part of the Poudrette quarry after the Demix quarry ceased operations and was sold to the Poudrette family in 1994. In late 2007 the Poudrette quarry changed ownership; the Poudrette family was no longer involved, and access changed dramatically. Modern collecting is highly restricted, with limited organized field trips for small groups rather than the broader access collectors remember from the quarry’s great producing years.
Analcime-bearing pockets range from small vugs to large zoned cavities. The most important specimens came from open pockets in the syenitic and pegmatitic environments where analcime could grow as free crystals with late-stage companions. The best older pieces often show careful trimming and extraction from pocket material rather than random quarry rubble; many are cabinet specimens from finds made when experienced local collectors had repeated access to fresh exposures.
Mont Saint-Hilaire analcime is typically colorless in smaller transparent crystals and white to gray in larger crystals. Luster is commonly vitreous on good crystal faces, and the best specimens show bright, sharp, well-formed trapezohedra rather than chalky masses. Smaller crystals may be transparent to translucent; large crystals are more often milky, translucent, or opaque white.
The signature habit is the trapezohedron, including classic sharp analcime crystals, distorted trapezohedra, and complex modified forms. Published locality descriptions report excellent trapezohedra to 25 cm and pseudomorphic masses to about 15 cm, with some Mindat locality notes recording very large crystals and pseudomorphs in zoned pockets. Most collector specimens on the market are far smaller: thumbnails to miniatures with crystals of a few millimeters to a few centimeters, and cabinet specimens with analcime crystals in the 2–5 cm range are already desirable when sharp, bright, and well associated.
Associations are a major quality factor. Analcime with black aegirine is the most immediately graphic combination: white geometric crystals against dark prismatic needles or sprays. Analcime with serandite or schizolite is the classic prestige combination, especially when the pink-orange pyroxenoid crystals are lustrous and undamaged. Natrolite adds delicate white acicular contrast; microcline or albite gives architectural feldspar matrix; rhodochrosite, siderite, polylithionite, catapleiite, fluorite, sodalite, calcite, and rare accessories can elevate a specimen from attractive to important.
Collectors should look closely at crystal skin. The best analcimes have crisp, lustrous faces and clean edges. Dull, granular, etched, or bruised faces are common enough and reduce value. Large white crystals may be impressive but can look blocky or opaque; smaller, more transparent, sharply developed crystals often make finer display specimens. A very large analcime from Mont Saint-Hilaire is not automatically a great specimen; the association, luster, crystal completeness, and balance of the whole piece matter more.
Pseudomorphs and casts are part of the locality’s personality. Analcime may occur in replacement textures or as crystalline masses after earlier minerals, and some specimens are valued because they record the pocket’s changing chemistry rather than because they are textbook single crystals. These pieces need accurate labeling: “analcime after unknown,” “analcime casts after serandite or aegirine,” or “analcime with possible pseudomorphic texture” is more honest than forcing a confident precursor when none has been demonstrated.
The main authenticity issue with Mont Saint-Hilaire analcime is not treatment but labeling precision. Genuine material is common enough that outright fabrication is not a major theme, but the locality’s name is used broadly and older labels may compress several quarry names into “Mont St-Hilaire.” A good label should ideally mention Poudrette quarry or Carrière Mont Saint-Hilaire, Québec, Canada, and older specimens may legitimately carry Demix, De-Mix, Uni-Mix, or Desourdy terminology depending on when and where they were collected.
The most common modern label complication concerns the pink-orange mineral paired with analcime. Many classic specimens were historically sold as serandite with analcime. Because serandite, schizolite, and pectolite form a compositional series, some salmon-colored Mont Saint-Hilaire material may require analysis to separate serandite from schizolite. For an analcime collector this does not diminish the visual appeal, but it does affect species labeling and price when the pink mineral is being advertised as the headline species.
Condition is critical. Analcime has good hardness for a zeolite-group mineral, but the crystals chip along edges and high points, and the snowy white surfaces show bruising easily. Matrix pieces with aegirine can shed needles; natrolite can be fragile; serandite or schizolite can have cleaved ends and contacts. Many otherwise attractive specimens have small pocket contacts, broken companion crystals, or repaired matrix. On fine combinations, inspect the analcime terminations and the exposed ends of associated serandite or schizolite blades.
High-quality Mont Saint-Hilaire analcime remains available, but the supply is increasingly dependent on old collections, dealer backstock, and the resale of specimens collected before access became severely restricted. Small analcime-on-aegirine or analcime-on-feldspar pieces can still be attainable. Good miniature and cabinet specimens with lustrous analcime and attractive associations are noticeably scarcer. Strong serandite or schizolite with analcime pieces, especially those with balanced composition and undamaged crystals, sit in a different market tier and are collected as classic Mont Saint-Hilaire specimens rather than merely as analcime examples.
In October 1996, Jean-Yves Lamoureux recovered a small but memorable analcime pocket that later became attached to one of the most reproduced Mont Saint-Hilaire analcime photographs. The largest analcime in that specimen was only 1.3 cm across, but the story behind it is pure quarry collecting. The cavity had already been opened and worked by another collector, Gilles, and it sat low in the wall along the road descending into the quarry. To reach it, Lamoureux had to crawl downward and left at roughly a 45-degree angle. He remembered having to empty his lungs to fit into the slanted chimney. It was mid-October, the outside air was about 45°F, and he was working without even a T-shirt. He stayed with the pocket for about four hours, pulling out “zillions of small analcimes” and later recalled that he “enjoyed every minute” of it. It is a perfect little Mont Saint-Hilaire scene: not a museum-scale crystal, not a glamorous pocket opening, but a determined collector wedged into a cold, awkward chimney because the sparkle of white trapezohedra kept coming.
Another Mont Saint-Hilaire field story from August 2002 shows why collectors never quite give up on an old wall. Daniel Comtois went to the Poudrette quarry with his father, Roland, on a sunny Sunday when expectations were low. The year had been poor for good finds; much of the recent work had been in hornfels-bearing rock, and a blast in syenite had exposed no pocket at all. Comtois had made only four collecting trips that season, three of them to Mont Saint-Hilaire. After driving around the quarry, he parked beside an old wall of very altered pegmatite—dark brown, rotten-looking material that other collectors did not expect to reward serious work.
He decided to dig anyway. A wooden stick was enough to pull fist-sized pieces from the decayed wall, and at first the open cavities gave only millimeter pyrite cubes. But he kept working deeper, placed rocks on the ground to read the zone, and eventually opened a pocket that changed the day. His father joined him by ladder. Broken crystals around the opening were sharp enough to cut their hands, but gloves would have cost them the fingertip sensitivity they needed. Comtois widened the pocket with chisel and sledge, peering inside between blows.
The first major thrill was quartz. He felt the faces of a giant smoky quartz crystal but did not immediately pull it into the sun; he believed hot sun could damage smoky quartz, so Roland fetched newspaper from the truck and the crystal went under the seat. More quartz followed—single crystals, complex twins, pieces he described as skeleton-like and cathedral-like, with windowed forms. Then came a specimen 24 cm long, a triangular cluster of three quartz groups around a central mass of microcline. Comtois thought the pocket had given its best.
It had not. As the broken material came out, large microcline plates appeared, some to about 13 x 13 cm. On one plate was a black sphalerite crystal that showed deep green when held to the sun. At the base of the plates he saw a dark rounded object, heavy for its size and rough under his fingertips. In daylight it proved to be a damage-free, gem-quality dark green sphalerite crystal. Several sphalerites came from the pocket, including a tetrahedral crystal about 9 x 9 x 8 cm. The day that began with other collectors saying there was nothing to find ended with giant quartz and sphalerite specimens packed under and over the seats of the truck.
For analcime collectors, the lesson is not that every wall hides a record sphalerite. It is that Mont Saint-Hilaire’s pockets were intensely localized. A few centimeters of altered pegmatite could be barren; a little deeper, a cavity could hold crystals that rewrote what collectors expected from the quarry.
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