Is diamond sharpening card profitable to sell on Amazon United States?

The niche generates $173K/yr across 39 tracked products. 0 of 1 products launched in the last 360 days are still selling. 90-day search growth is -1.1%. Flapen's verdict: Worth a look (50/100).

How competitive is the diamond sharpening card niche?

8 brands and 111 sellers compete. The top 5 products take 42% of clicks and top 5 brands hold 97% of demand.

What do buyers complain about in diamond sharpening card?

Top complaints mined from reviews: Sharpness, Quality-Overall, Durability. The return rate is 1.3%.

When does demand for diamond sharpening card peak?

Demand peaks in Jan–Dec; the busiest month runs 1.8× the quietest.

What does it cost to enter the diamond sharpening card niche?

Listings span $11.63–$146.76; the average listing price is $44.58 (sweet spot $15–$100). The average incumbent carries 835 reviews — the moat a new listing must climb.

diamond sharpening card

Worth a look

Shows a sweet-spot price point ($44.58 avg), but brand-locked demand (top 5 brands take 97% of clicks) keeps it on the watch list.

Avg price

Incredible$44.58

avg listing price — sweet spot $15–$100

Returns

Great1.3%

return rate — above 5% kills the launch gate

Competition

Good42%

top-5 click share — leaders hold, buyers still browse

Review moat

Good835.23

avg incumbent reviews — the moat a new listing must climb

Price range

Good$11.63–$146.76

cheapest to priciest tracked listing — scored on the share inside $15–$100

Conversion

Good4.0%

search→purchase rate — share of searches ending in a sale

Quality gap

Okay4.5★

avg incumbent rating — lower means beatable quality

Market size

Okay$173K

$173K/yr · 97K searches

Growth

Bad-1.1%

90-day search growth — must beat 0% to launch

Brand share

Bad97%

top-5 brand share — brand-locked demand

According to Flapen's Amazon United States niche tracking, diamond sharpening card is a $173K/yr Amazon United States market (97K searches/yr). The top 5 brands hold 97% of demand. Demand peaks in Jan–Dec. Verdict: Worth a look — 50/100.

Data updated Jul 29, 2026 · scored weekly · How we score niches

diamond sharpening card market data

Units sold / yr: 3K–4K; avg 0–100/product
Revenue / yr: $134K–$178K; units × avg price
Conversion rate: 4.0%
Avg BSR: #1,082
Page quality: 0%
Prime: 100%
Sponsored: 56%
Out of stock: 0.5%
Avg brand age: 75 months
Avg seller age: 171 days

Competition & brand share

The top 5 products take 42% of clicks — established leaders, but buyers still shop beyond them.

Brands

8 rising

Sellers

111

Top-5 brand share

97%

Top 20: 100%

Top-5 click share

42%

Top 20: 82%

Open market

DMT (Diamond Machining Technology)73%
EZE-LAP12%
TREND6%
SHARPAL5%
Ultrasharp2%
Mysora1%
Open — no brand owns it (2 brands, 2%)

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — -1.1% search growth over the last 90 days.

Peak months: Jan, Dec · busiest ÷ quietest = 1.8×

Open Trend

Top diamond sharpening card search terms

dmt diamond sharpening stone47K/yr +3.4%1.9% conv.
dmt knife sharpener9K/yr +28.1%2.1% conv.
eze lap diamond stone9K/yr -23.8%2.8% conv.
dmt sharpening stone8K/yr +10.9%1.4% conv.
lapping fluid4K/yr +0.7%9.2% conv.
diamond sharpening card4K/yr -14.8%5.0% conv.
eze lap diamond sharpener3K/yr +30.8%4.5% conv.
router bit sharpener4K/yr -22.9%1.4% conv.
dmt sharpener4K/yr -26.7%3.1% conv.
eze-lap2K/yr +9.9%2.8% conv.

All search terms

Top diamond sharpening card products on Amazon

Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.

Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

All 24 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

DMT D8F Dia-Sharp Bench Stone - Diamond Knife Sharpener for the Workshop Jobsite or Kitchen - Fine - Flat Diamond Sharpening - Non-Slip Knife Sharpener- Made in the USA - 8 x 3 x 0.38 Inches

DMT (Diamond Machining Technology)$39.724.5★1,130 rev

DMT FWFC DuoSharp Double-Sided Diamond Sharpening Stone for Knives and More 8-Inch Fine/Coarse White

DMT (Diamond Machining Technology)$25.064.6★1,383 rev

DMT Deluxe Diamond Professional Knife Sharpening Kit - Includes Set of 3 Diamond Whetstone Blocks for Kitchen Knives Lawn Mower Blades Hunting/Butchery Tools and More - Comes in Natural Wood Box

DMT (Diamond Machining Technology)$104.064.5★1,766 rev

DMT D8C Dia-Sharp Bench Stone - Diamond Knife Sharpener for the Workshop Jobsite or Kitchen - Coarse (325) - Flat Diamond Sharpening - Non-Slip Knife Sharpener- Made in the USA - 8 x 3 x 0.38 Inches

DMT (Diamond Machining Technology)$49.714.4★892 rev

DMT DuoSharp Double-Sided Diamond Whetstone - Fine/Coarse (600/325) Diamond Sharpening Stone with Base - Tool Sharpener for Kitchen Garage Workshop Chisels Knives More - Made in USA 8 Inches

DMT (Diamond Machining Technology)$75.794.6★672 rev

Newest

by launch date

Mysora Diamond Abrasive Lapping Fluid 3.4 fl oz (100 ml) Honing Oil for Diamond Stones & Knife Sharpening Precision Tip Applicator Prevents Clogging & Rust Improves Grinding Performance

Mysora$11.639 rev

5mo ago

SHARPAL 162N Double-sided Diamond Sharpening Stone 8 in. x 3 in.

SHARPAL$66.986,988 rev

7y ago

SHARPAL 116N Pocket Diamond Sharpening Card

SHARPAL$26.68878 rev

7y ago

DMT D8E Dia-Sharp Bench Stone - Diamond Knife Sharpener for the Workshop Jobsite or Kitchen - Extra Fine- Flat Diamond Sharpening - Non-Slip Knife Sharpener- Made in the USA - 8 x 3 x 0.38 Inches

DMT (Diamond Machining Technology)$56.18632 rev

8y ago

Ultra Sharp Diamond Sharpening Stone Set - 8 x 3 Coarse/Medium/Extra Fine

Ultrasharp$138.161,122 rev

10y ago

What buyers say about diamond sharpening card

What buyers praise and complain about, mined from review topics.

What buyers love

Sharpness24%

“Sharp tools”

Quality-Overall16%

“Long lasting quality”

Value For Money12%

“For the price”

Durability8%

“extremely durable”

Ease Of Use6%

“Very easy to use”

Advertised Vs Actual Product5%

“works as advertised”

Precision Of Cut4%

“Works well to get a sharp blade”

Efficiency2%

“Works very well”

Ease Of Cleaning2%

“It keeps the diamond stone cleaner”

Size-Overall2%

“I really like this little stone because it's so small”

What buyers complain about

Sharpness16%

“You cant get it razor sharp”

Quality-Overall15%

“Horrible quality”

Durability14%

“Lack Durability”

Material Quality6%

“Very poor quality plastic”

Value For Money5%

“way over priced”

Size-Overall3%

“it would not fit”

Rusts/Corrodes3%

“the medium grit blue block started to rust within an hour”

Functionality-Overall2%

“It is not working”

Product Condition2%

“at that I recall ordering a NEW ITEM not used”

Weight Heavy2%

“is quite heavy”

Top return reasons

Sharpness29%

Size-Overall14%

Functionality-Overall9%

Advertised Vs Actual Product9%

Product Condition9%

Value For Money8%

Quality-Overall5%

Defective Material/Parts3%

Durability2%

Rusts/Corrodes2%

Common questions

Is diamond sharpening card profitable to sell on Amazon United States?: The niche generates $173K/yr across 39 tracked products. 0 of 1 products launched in the last 360 days are still selling. 90-day search growth is -1.1%. Flapen's verdict: Worth a look (50/100).
How competitive is the diamond sharpening card niche?: 8 brands and 111 sellers compete. The top 5 products take 42% of clicks and top 5 brands hold 97% of demand.
What do buyers complain about in diamond sharpening card?: Top complaints mined from reviews: Sharpness, Quality-Overall, Durability. The return rate is 1.3%.
When does demand for diamond sharpening card peak?: Demand peaks in Jan–Dec; the busiest month runs 1.8× the quietest.
What does it cost to enter the diamond sharpening card niche?: Listings span $11.63–$146.76; the average listing price is $44.58 (sweet spot $15–$100). The average incumbent carries 835 reviews — the moat a new listing must climb.