Owen Missen

Cuprite is still in with chance! Copper does form a few Cu 1+ minerals but mostly these are sulfides or sulfosalts e.g. chalcocite (Cu2S), as an oxide mineral cuprite is unusual!

Famously versatile and flaky! Graphite's structure is in the high school chemistry curriculum. It conducts electricity and is very soft, leading to its uses in grey 'lead' pencils and as a solid lubricant. Carbon has 5 polymorphs: graphite, diamond, lonsdaleite, chaoite and tartarosite.

Ten years after Mineral Cup began, the mineral that began it all, quartz, is into the semi finals. Quartz is the most common SiO2 polymorph, but there are 8 other known polymorphs of SiO2 (cristobalite, tridymite, coesite, lechatelierite, moganite, seifertite, stishovite and xiexiandeite).

Cuprite is red as the copper is in copper 1+ oxidation state, not copper 2+ which has the more common blues and greens - competing against halite, best known as an evaporite mineral. Salty fluids are also key to transporting metals in both hydrothermal and surface environments as chloride complexes!

Pyromorphite vs cylindrite, both lead containing minerals but very different! Pyromorphite (Pb5(PO4)3Cl) - apatite structure, found in oxidised zones of lead deposits. Cylindrite (Pb3Sn4FeSb2S14) - sulfide mineral with an unusual cylindrical structural habit, due to incommensurate modulation.

Putnisite contains essential chromium - like stichtite yesterday - while julienite's vibrant blue comes not from copper, but from cobalt! Putnisite: SrCa4Cr3+8(CO3)8SO4(OH)16 · 23H2O Julienite: Na2[Co(SCN)4] · 8H2O NB: SCN- is the thiocyanate anion, julienite is the only mineral known with SCN!

This is the kind of Mineral Cup match up that is particularly enjoyable for me. Admittedly, neither of these two minerals are common, and nor do they have major uses. But they remind us of the wonder of the natural world and its ability to produce amazing crystals!

A vote for silvery skutterudite is also a vote for bright pink erythrite, vanquished last round in the battle of cobalt-arsenic minerals! Let's join forces rather than revenge vote this time 😅

cassiterite is 100 votes behind, needs a miracle! keep those votes coming!

Xocolatlite is a tellurium mineral with a great name, and features in the 10th edition of Mineral Cup, five years after the most unlikely of champions, quetzalcoatlite! Xocolatlite also has the distinction of being described by my phd supervisor Joel Brugger and team!

Chrysocolla is beautiful but I had to draw something for Xocolatlite #MinCup26

I confess that before this Mineral Cup I had never heard of julienite! It's our third cobalt mineral of 2026, and is a coordination compound salt containing the thiocyanate anion. You don't see formulae like Na2[Co(SCN)4]·8H2O too often, julienite is the only SCN mineral yet known!

Calcite hardly needs an introduction. Its reactivity with acid and 3 strong cleavage planes (great when teaching first year mineralogy), amazing variety of forms and importance for CO2 storage give us plenty of reasons that calcite might be a favourite.

Not quite sure how #pyromorphite will fare against the (literal) crystal juggernaut that is #gypsum - but I really liked the (VESTA default) halloween-esque colour scheme to it's elements to day so the small green crystal machine gets my vote in today's #MinCup26

Beautiful, twinned, translucent, and hexagonal prisms of lead-bearing, apple-green pyromorphite. Relatively safe if basic safety rules are taken, and highly collectible, but NO licking. #MinCup26 ⚒️ sci-fi 🧪 🖖🏼 scifi Geosciences #WomenInSTEM geology #geosky #GIS 🍎 🪐 🔭 🌋 📚 🌿

Gypsum is a beautifully versatile mineral, found in a range of sedimentary environments, sometimes in flower shaped forms ('desert rose' isn't a flower, but gypsum - often with some quartz grains!). Gypsum is widely used in construction, particularly in plaster and cement-making applications.

Pyromorphite sounds like some kind of fire demon, the name actually coming from its behaviour of reforming crystals after being melted into a globule! Old names included 'plumbo viridis' (green lead - pyromorphite being lead phosphate chloride). Vanadinite (V swapped for P) shares this structure!

Hafnium's only mineral up against purple putnisite. Second beautiful purple chromium 3+ mineral in two days, with some chemical similarities (group 2 metal - chromium - carbonate - hydroxide - hydrate). Stichtite: Mg6Cr3+2(OH)16[CO3] · 4H2O Putnisite: SrCa4Cr3+8(CO3)8SO4(OH)16 · 23H2O

Stichtite is particularly famous in Tasmania, first found from appropriately named Stichtite Hill (not sure what the previous name of the site was!). It's the most famous mineral first found in Tasmania, although crocoite is Tasmania's state mineral emblem. Both contain soluble chromium!

Monazite doubles as a source of (mainly light) rare-earth elements and as a geochronometer, due to the uranium and thorium often incorporated into its crystal structure . Monazite-(Ce) is the most common form, with La, Nd, Sm and Gd dominant monazites also known in decreasing order of commonality.

Quartz's apparent supremacy as the best mineral was the reason behind Eddie Dempsey creating the first Mineral Cup on Twitter back in 2017! Despite its importance to a wide range of geological and mineralogical sciences, quartz has never yet managed to win Mineral Cup. Could this be the year?

Asagiite is a new member of the ktenasite group, a class of hydrated basic metal sulfates that so far numbers four minerals, so far all in the form MCu4(SO4)2(OH)6.6H2O although analogues with different metals in the Cu site are possible. M=Ni in asagiite 'blue-green' in Japanese!

Orpiment was historically used as a pigment, taking advantage of its bright yellow-orange colour. However, orpiment is arsenic trisulfide (As2S3) and thus is very rarely used today. Fellow arsenic sulfide mineral realgar (As4S4) is bright red-orange... and also toxic!

#Bournonite has 4 elements. Some lovely rare metals in the mix, and it can solid-solution on over to incorporate a 5th, but it’d very well-defined. Meanwhile, I straight-up gave up listing all the possible elements in #Vesuvianite because it was too freaking long. The rest. It has all the rest.

Bournonite for me! This sulfosalt is formed by lead, copper, antimony and sulfur. Another six minerals contain only these four elements and eleven further sulfosalts have Pb Cu Sb plus other metal(loid)s but bournonite is by far the most common of all of them!

Voting for zinc sulfide sphalerite! Sphalerite is also an important host for strategic metal zinc, plus a range of critical metals, especially gallium, germanium and indium (though not usually all three of them in the same crystals). www.mindat.org/photo-253687...

cobalt vs cobalt! hard to pick here, and I love the weathering product vs the primary mineral!

carbonate vs carbonate! it's azurite for me, though it still astounds me that the simple form of copper carbonate CuCO3 is not found in nature. copper carbonates always have some OH to stabilise the structures in malachite and azurite!

correction from earlier post (about semi final 2 still!), it's native copper vs molybdenite in the final! easier one for me, much as I love copper minerals I'll go with the soft sulfide!

quick game's a good game and it's already the Ore Cup final! very hard one to pick for me! both beautiful and important sulfide minerals 🥰🥰

correct prediction! we'll see if molybdenite can make it to the final!

We’re on team #molybdenite in today’s #OreCup match-up. It’s the main ore of molybdenum, a critical resource with many uses, including in building renewable energy technologies. eos.org/features/cri...

We didn’t always recognize #Molybdenite or know how to use Mo until the late 19th Century. Rh wasn’t discovered until 1908. After early experiments during WWI, automobile and aviation industries found uses for both elements in high-performance alloys. Then catalysts and medical uses. #OreCup25 ⚒️ 🧪

Copper has my heart.

Congratulations to #Copper on a winning by a decisive 27% margin. Whatever happens in the Finals, you won’t be going home with bronze. Condolences, #Ilmenite, but we’re confident you’ll weather this setback with your usual resilience.

#OreCup R2M2: It's slippery and silvery #Molybdenite vs peacock rock #Bornite! Are you supporting the only molybdenum (and rhenium) ore, or the hefty copper sulphide? vote: www.mineralcup.org/vote-results... results: www.mineralcup.org/vote-results...

#OreCup tis the season! anyone want to write a ... Carroll? O Cobalt Ye Faithful 😅

Carrollite, Japon youtu.be/a_z5HVAkAWk #carrollite #sulfur #quartz #unique #cristaux #cristal #crystals #mineralogie #mineraux #minerai #gemmes #gems #collection #naturae #lapides #minerals #nature #merveille #cristallisation #collector www.youtube.com/@naturaelapi...

Nice article on the type locality of #carrollite : Carroll County, Maryland and the Patapsco Mine. https://jamesrada.com/carrollite-the-mineral-once-found-only-in-carroll-county/ #OreCup #OreCup25 #MinCup25 #Maryland #Sykesville #Cobalt

#Carrollite from Congo at the Tucson show #OreCup #MineralMonday

Octahedral crystals, polysynthetic twinning striations, super conductivity, and iridescent sheen? Yes, please. #carrollite #MinCup25 ⚒️ sci-fi 🧪 🖖🏼 scifi Geosciences #WomenInSTEM geology 🔭🪐