Forshammar Feldspar (Sibelco, Sweden)

What it is

Kind

Feldspars and stones

Status

Hard to get

Formula

SiO₂ 75.6%, Al₂O₃ 14.5%, Na₂O 4.8%, K₂O 4.2%, CaO 0.2%, MgO 0.1%, TiO₂ 0.002%, Fe₂O₃ 0.17%

Also called

Forshammar 60, Forshammar, Forshammar fältspat, Forshammar feldspar

Made by

Sibelco Nordic AB (Forshammar quarry, Riddarhyttan, Sweden)

Sold in

EU

Similar materials

FFP 45 Feldspar , FFF Feldspar (Sibelco FFF K7-60) , H&G Cornwall Stone , Cornish Stone, Synthetic (Walker BA280)

Source

Sibelco ceramics product selector, feldspars for glazes and engobes (Forshammar 60, origin SE) (2021-06)

Swedish feldspar-quartz rock from Sibelco's Forshammar quarry, with about equal soda and potash and much free silica. Forshammar feldspar is named in many older Swedish stoneware recipes, but Swedish and UK pottery suppliers now sell Finnish FFF or FFP 45 in its place.

Oxide analysis and unity formula

Glazecalc has the analysis of Forshammar Feldspar (Sibelco, Sweden) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Forshammar Feldspar (Sibelco, Sweden) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.

Equivalent weight

780.75

Fired weight

780.75

Loss on ignition

0%

The equivalent weight is the grams of Forshammar Feldspar (Sibelco, Sweden) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.

Hazards and safety

Hazards: High in free quartz (SiO2 about 76%); the dust contains respirable crystalline silica. Avoid breathing it.

Glazecalc shows the hazard wording as its record gives it. It is not a full risk assessment, so read the safety data sheet from your supplier. Before you handle any glaze material, read Safe mixing and ventilation and Glaze safety at home.

Use it in a recipe

Add Forshammar Feldspar (Sibelco, Sweden) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.

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